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1. Erratum: 'The NANOGrav 15 yr Data Set: Search for Signals from New Physics' (2023, ApJL 951 L11)

Author

Adeela Afzal, Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Jose Juan Blanco-Pillado, Laura Blecha, Kimberly K. Boddy, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, Maria Charisi, Shami Chatterjee, Katerina Chatziioannou, Belinda D. Cheeseboro, Siyuan Chen, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Curt J. Cutler, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Heling Deng, Timothy Dolch, Brendan Drachler, Richard von Eckardstein, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Lydia Guertin, Kayhan Gültekin, Jeffrey S. Hazboun, Sophie Hourihane, Kristina Islo, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Vincent S. H. Lee, Natalia Lewandowska, Rafael R. Lino dos Santos, Tyson B. Littenberg, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Jonathan Nay, Priyamvada Natarajan, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Tobias Schröder, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Peter Stratmann, Jerry P. Sun, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Tanner Trickle, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sonali Verma, Sarah J. Vigeland, Haley M. Wahl, Qiaohong Wang, Caitlin A. Witt, David Wright, Olivia Young, Kathryn M. Zurek, and The NANOGrav Collaboration

Subjects
Astrophysics, QB460-466
Published
2024
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2. The NANOGrav 15 yr Data Set: Search for Transverse Polarization Modes in the Gravitational-wave Background

Author

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Jeremy Baier, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Priyamvada Natarajan, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Alexander Saffer, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Jerry P. Sun, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob A. Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational waves, Pulsars, Scalar-tensor-vector gravity, Astrophysics, QB460-466
Abstract

Recently we found compelling evidence for a gravitational-wave background with Hellings and Downs (HD) correlations in our 15 yr data set. These correlations describe gravitational waves as predicted by general relativity, which has two transverse polarization modes. However, more general metric theories of gravity can have additional polarization modes, which produce different interpulsar correlations. In this work, we search the NANOGrav 15 yr data set for evidence of a gravitational-wave background with quadrupolar HD and scalar-transverse (ST) correlations. We find that HD correlations are the best fit to the data and no significant evidence in favor of ST correlations. While Bayes factors show strong evidence for a correlated signal, the data does not strongly prefer either correlation signature, with Bayes factors ∼2 when comparing HD to ST correlations, and ∼1 for HD plus ST correlations to HD correlations alone. However, when modeled alongside HD correlations, the amplitude and spectral index posteriors for ST correlations are uninformative, with the HD process accounting for the vast majority of the total signal. Using the optimal statistic, a frequentist technique that focuses on the pulsar-pair cross-correlations, we find median signal-to-noise ratios of 5.0 for HD and 4.6 for ST correlations when fit for separately, and median signal-to-noise ratios of 3.5 for HD and 3.0 for ST correlations when fit for simultaneously. While the signal-to-noise ratios for each of the correlations are comparable, the estimated amplitude and spectral index for HD are a significantly better fit to the total signal, in agreement with our Bayesian analysis.

Published
2024
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3. The NANOGrav 12.5 yr Data Set: A Computationally Efficient Eccentric Binary Search Pipeline and Constraints on an Eccentric Supermassive Binary Candidate in 3C 66B

Author

Gabriella Agazie, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Laura Blecha, Harsha Blumer, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Belinda D. Cheeseboro, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Lankeswar Dey, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Achamveedu Gopakumar, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Kai Schmitz, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Sophia V. Sosa Fiscella, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational waves, Millisecond pulsars, Supermassive black holes, Astrophysics, QB460-466
Abstract

The radio galaxy 3C 66B has been hypothesized to host a supermassive black hole binary (SMBHB) at its center based on electromagnetic observations. Its apparent 1.05 yr period and low redshift (∼0.02) make it an interesting testbed to search for low-frequency gravitational waves (GWs) using pulsar timing array (PTA) experiments. This source has been subjected to multiple searches for continuous GWs from a circular SMBHB, resulting in progressively more stringent constraints on its GW amplitude and chirp mass. In this paper, we develop a pipeline for performing Bayesian targeted searches for eccentric SMBHBs in PTA data sets, and test its efficacy by applying it to simulated data sets with varying injected signal strengths. We also search for a realistic eccentric SMBHB source in 3C 66B using the NANOGrav 12.5 yr data set employing PTA signal models containing Earth term-only as well as Earth+pulsar term contributions using this pipeline. Due to limitations in our PTA signal model, we get meaningful results only when the initial eccentricity e _0 < 0.5 and the symmetric mass ratio η > 0.1. We find no evidence for an eccentric SMBHB signal in our data, and therefore place 95% upper limits on the PTA signal amplitude of 88.1 ± 3.7 ns for the Earth term-only and 81.74 ± 0.86 ns for the Earth+pulsar term searches for e _0 < 0.5 and η > 0.1. Similar 95% upper limits on the chirp mass are (1.98 ± 0.05) × 10 ^9 and (1.81 ± 0.01) × 10 ^9 M _☉ . These upper limits, while less stringent than those calculated from a circular binary search in the NANOGrav 12.5 yr data set, are consistent with the SMBHB model of 3C 66B developed from electromagnetic observations.

Published
2024
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4. The NANOGrav 12.5 yr Data Set: Search for Gravitational Wave Memory

Author

Gabriella Agazie, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Laura Blecha, Harsha Blumer, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Nihan S. Pol, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Kai Schmitz, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Sophia V. Sosa Fiscella, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Jerry P. Sun, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational waves, Gravitational wave astronomy, Astrophysics, QB460-466
Abstract

We present the results of a Bayesian search for gravitational wave (GW) memory in the NANOGrav 12.5 yr data set. We find no convincing evidence for any gravitational wave memory signals in this data set. We find a Bayes factor of 2.8 in favor of a model that includes a memory signal and common spatially uncorrelated red noise (CURN) compared to a model including only a CURN. However, further investigation shows that a disproportionate amount of support for the memory signal comes from three dubious pulsars. Using a more flexible red-noise model in these pulsars reduces the Bayes factor to 1.3. Having found no compelling evidence, we go on to place upper limits on the strain amplitude of GW memory events as a function of sky location and event epoch. These upper limits are computed using a signal model that assumes the existence of a common, spatially uncorrelated red noise in addition to a GW memory signal. The median strain upper limit as a function of sky position is approximately 3.3 × 10 ^−14 . We also find that there are some differences in the upper limits as a function of sky position centered around PSR J0613−0200. This suggests that this pulsar has some excess noise that can be confounded with GW memory. Finally, the upper limits as a function of burst epoch continue to improve at later epochs. This improvement is attributable to the continued growth of the pulsar timing array.

Published
2024
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5. The NANOGrav 15 yr Data Set: Search for Anisotropy in the Gravitational-wave Background

Author

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko Gardiner, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, and Olivia Young

Subjects
Gravitational waves, Gravitational wave astronomy, Supermassive black holes, Pulsars, Astrophysics, QB460-466
Abstract

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has reported evidence for the presence of an isotropic nanohertz gravitational-wave background (GWB) in its 15 yr data set. However, if the GWB is produced by a population of inspiraling supermassive black hole binary (SMBHB) systems, then the background is predicted to be anisotropic, depending on the distribution of these systems in the local Universe and the statistical properties of the SMBHB population. In this work, we search for anisotropy in the GWB using multiple methods and bases to describe the distribution of the GWB power on the sky. We do not find significant evidence of anisotropy. By modeling the angular power distribution as a sum over spherical harmonics (where the coefficients are not bound to always generate positive power everywhere), we find that the Bayesian 95% upper limit on the level of dipole anisotropy is ( C _l _=1 / C _l _=0 ) < 27%. This is similar to the upper limit derived under the constraint of positive power everywhere, indicating that the dipole may be close to the data-informed regime. By contrast, the constraints on anisotropy at higher spherical-harmonic multipoles are strongly prior dominated. We also derive conservative estimates on the anisotropy expected from a random distribution of SMBHB systems using astrophysical simulations conditioned on the isotropic GWB inferred in the 15 yr data set and show that this data set has sufficient sensitivity to probe a large fraction of the predicted level of anisotropy. We end by highlighting the opportunities and challenges in searching for anisotropy in pulsar timing array data.

Published
2023
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6. The NANOGrav 15 yr Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational-wave Background

Author

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Paul T. Baker, Bence Bécsy, Laura Blecha, Alexander Bonilla, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Katerina Chatziioannou, Belinda D. Cheeseboro, Siyuan Chen, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Curt J. Cutler, Daniel J. D’Orazio, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Heling Deng, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko Gardiner, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Sophie Hourihane, Kristina Islo, Ross J. Jennings, Aaron Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tyson B. Littenberg, Tingting Liu, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Priyamvada Natarajan, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Jessie C. Runnoe, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Jerry P. Sun, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Jeremy M. Wachter, Haley M. Wahl, Qiaohong Wang, Caitlin A. Witt, David Wright, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational waves, Supermassive black holes, Galaxy evolution, Astrophysics, QB460-466
Abstract

The NANOGrav 15 yr data set shows evidence for the presence of a low-frequency gravitational-wave background (GWB). While many physical processes can source such low-frequency gravitational waves, here we analyze the signal as coming from a population of supermassive black hole (SMBH) binaries distributed throughout the Universe. We show that astrophysically motivated models of SMBH binary populations are able to reproduce both the amplitude and shape of the observed low-frequency gravitational-wave spectrum. While multiple model variations are able to reproduce the GWB spectrum at our current measurement precision, our results highlight the importance of accurately modeling binary evolution for producing realistic GWB spectra. Additionally, while reasonable parameters are able to reproduce the 15 yr observations, the implied GWB amplitude necessitates either a large number of parameters to be at the edges of expected values or a small number of parameters to be notably different from standard expectations. While we are not yet able to definitively establish the origin of the inferred GWB signal, the consistency of the signal with astrophysical expectations offers a tantalizing prospect for confirming that SMBH binaries are able to form, reach subparsec separations, and eventually coalesce. As the significance grows over time, higher-order features of the GWB spectrum will definitively determine the nature of the GWB and allow for novel constraints on SMBH populations.

Published
2023
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7. The NANOGrav 15 yr Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries

Author

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Robin Case, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Matthew C. Digman, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Sophie Hourihane, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Rutger van Haasteren, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational wave astronomy, Astrophysics, QB460-466
Abstract

Evidence for a low-frequency stochastic gravitational-wave background has recently been reported based on analyses of pulsar timing array data. The most likely source of such a background is a population of supermassive black hole binaries, the loudest of which may be individually detected in these data sets. Here we present the search for individual supermassive black hole binaries in the NANOGrav 15 yr data set. We introduce several new techniques, which enhance the efficiency and modeling accuracy of the analysis. The search uncovered weak evidence for two candidate signals, one with a gravitational-wave frequency of ∼4 nHz, and another at ∼170 nHz. The significance of the low-frequency candidate was greatly diminished when Hellings–Downs correlations were included in the background model. The high-frequency candidate was discounted due to the lack of a plausible host galaxy, the unlikely astrophysical prior odds of finding such a source, and since most of its support comes from a single pulsar with a commensurate binary period. Finding no compelling evidence for signals from individual binary systems, we place upper limits on the strain amplitude of gravitational waves emitted by such systems. At our most sensitive frequency of 6 nHz, we place a sky-averaged 95% upper limit of 8 × 10 ^−15 on the strain amplitude. We also calculate an exclusion volume and a corresponding effective radius, within which we can rule out the presence of black hole binaries emitting at a given frequency.

Published
2023
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8. The NANOGrav 12.5 yr Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries

Author

Zaven Arzoumanian, Paul T. Baker, Laura Blecha, Harsha Blumer, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Bence Bécsy, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Siyuan Chen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Justin A. Ellis, E. C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nathan Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Nima Laal, Michael T. Lam, William G Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Dustin R. Madison, Alexander McEwen, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Nihan S. Pol, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena Siwek, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Joseph K. Swiggum, Jessica Sydnor, Stephen R. Taylor, Jacob E. Turner, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Gregory Walsh, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational waves, Astronomy data analysis, Millisecond pulsars, Supermassive black holes, Astrophysics, QB460-466
Abstract

Pulsar timing array collaborations, such as the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), are seeking to detect nanohertz gravitational waves emitted by supermassive black hole binaries formed in the aftermath of galaxy mergers. We have searched for continuous waves from individual circular supermassive black hole binaries using NANOGrav’s recent 12.5 yr data set. We created new methods to accurately model the uncertainties on pulsar distances in our analysis, and we implemented new techniques to account for a common red-noise process in pulsar timing array data sets while searching for deterministic gravitational wave signals, including continuous waves. As we found no evidence for continuous waves in our data, we placed 95% upper limits on the strain amplitude of continuous waves emitted by these sources. At our most sensitive frequency of 7.65 nHz, we placed a sky-averaged limit of h _0 < (6.82 ± 0.35) × 10 ^−15 , and h _0 < (2.66 ± 0.15) × 10 ^−15 in our most sensitive sky location. Finally, we placed a multimessenger limit of ${ \mathcal M }\lt (1.41\pm 0.02)\times {10}^{9}\,{M}_{\odot }$ on the chirp mass of the supermassive black hole binary candidate 3C 66B.

Published
2023
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9. The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background

Author

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, Maria Charisi, Shami Chatterjee, Katerina Chatziioannou, Belinda D. Cheeseboro, Siyuan Chen, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Curt J. Cutler, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Heling Deng, Timothy Dolch, Brendan Drachler, Justin A. Ellis, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Sophie Hourihane, Kristina Islo, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Tonia C. Klein, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tyson B. Littenberg, Tingting Liu, Andrea Lommen, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Margaret A. Mattson, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Priyamvada Natarajan, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Jerry P. Sun, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Rutger van Haasteren, Sarah J. Vigeland, Haley M. Wahl, Qiaohong Wang, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Gravitational waves, Gravitational wave astronomy, Millisecond pulsars, Radio pulsars, Supermassive black holes, Astrophysics, QB460-466
Abstract

We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. The correlations follow the Hellings–Downs pattern expected for a stochastic gravitational-wave background. The presence of such a gravitational-wave background with a power-law spectrum is favored over a model with only independent pulsar noises with a Bayes factor in excess of 10 ^14 , and this same model is favored over an uncorrelated common power-law spectrum model with Bayes factors of 200–1000, depending on spectral modeling choices. We have built a statistical background distribution for the latter Bayes factors using a method that removes interpulsar correlations from our data set, finding p = 10 ^−3 (≈3 σ ) for the observed Bayes factors in the null no-correlation scenario. A frequentist test statistic built directly as a weighted sum of interpulsar correlations yields p = 5 × 10 ^−5 to 1.9 × 10 ^−4 (≈3.5 σ –4 σ ). Assuming a fiducial f ^−2/3 characteristic strain spectrum, as appropriate for an ensemble of binary supermassive black hole inspirals, the strain amplitude is ${2.4}_{-0.6}^{+0.7}\times {10}^{-15}$ (median + 90% credible interval) at a reference frequency of 1 yr ^−1 . The inferred gravitational-wave background amplitude and spectrum are consistent with astrophysical expectations for a signal from a population of supermassive black hole binaries, although more exotic cosmological and astrophysical sources cannot be excluded. The observation of Hellings–Downs correlations points to the gravitational-wave origin of this signal.

Published
2023
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10. The NANOGrav 15 yr Data Set: Observations and Timing of 68 Millisecond Pulsars

Author

Gabriella Agazie, Md Faisal Alam, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Laura Blecha, Victoria Bonidie, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Bence Bécsy, Christopher Chapman, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Cody Jessup, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Anastasia Kuske, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Ye Lin, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Kaleb Maraccini, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Elisa Panciu, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Laura Salo, Shashwat C. Sardesai, Carl Schmiedekamp, Ann Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Qiaohong Wang, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Millisecond pulsars, Pulsar timing method, Time series analysis, Pulsars, Gravitational waves, Astrophysics, QB460-466
Abstract

We present observations and timing analyses of 68 millisecond pulsars (MSPs) comprising the 15 yr data set of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). NANOGrav is a pulsar timing array (PTA) experiment that is sensitive to low-frequency gravitational waves (GWs). This is NANOGrav’s fifth public data release, including both “narrowband” and “wideband” time-of-arrival (TOA) measurements and corresponding pulsar timing models. We have added 21 MSPs and extended our timing baselines by 3 yr, now spanning nearly 16 yr for some of our sources. The data were collected using the Arecibo Observatory, the Green Bank Telescope, and the Very Large Array between frequencies of 327 MHz and 3 GHz, with most sources observed approximately monthly. A number of notable methodological and procedural changes were made compared to our previous data sets. These improve the overall quality of the TOA data set and are part of the transition to new pulsar timing and PTA analysis software packages. For the first time, our data products are accompanied by a full suite of software to reproduce data reduction, analysis, and results. Our timing models include a variety of newly detected astrometric and binary pulsar parameters, including several significant improvements to pulsar mass constraints. We find that the time series of 23 pulsars contain detectable levels of red noise, 10 of which are new measurements. In this data set, we find evidence for a stochastic GW background.

Published
2023
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11. The NANOGrav 15 yr Data Set: Detector Characterization and Noise Budget

Author

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Lydia Guertin, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, Olivia Young, and The NANOGrav Collaboration

Subjects
Millisecond pulsars, Pulsar timing method, Gravitational wave astronomy, Gravitational wave detectors, Radio astronomy, Astrophysics, QB460-466
Abstract

Pulsar timing arrays (PTAs) are galactic-scale gravitational wave (GW) detectors. Each individual arm, composed of a millisecond pulsar, a radio telescope, and a kiloparsecs-long path, differs in its properties but, in aggregate, can be used to extract low-frequency GW signals. We present a noise and sensitivity analysis to accompany the NANOGrav 15 yr data release and associated papers, along with an in-depth introduction to PTA noise models. As a first step in our analysis, we characterize each individual pulsar data set with three types of white-noise parameters and two red-noise parameters. These parameters, along with the timing model and, particularly, a piecewise-constant model for the time-variable dispersion measure, determine the sensitivity curve over the low-frequency GW band we are searching. We tabulate information for all of the pulsars in this data release and present some representative sensitivity curves. We then combine the individual pulsar sensitivities using a signal-to-noise ratio statistic to calculate the global sensitivity of the PTA to a stochastic background of GWs, obtaining a minimum noise characteristic strain of 7 × 10 ^−15 at 5 nHz. A power-law-integrated analysis shows rough agreement with the amplitudes recovered in NANOGrav’s 15 yr GW background analysis. While our phenomenological noise model does not model all known physical effects explicitly, it provides an accurate characterization of the noise in the data while preserving sensitivity to multiple classes of GW signals.

Published
2023
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12. The NANOGrav 15 yr Data Set: Search for Signals from New Physics

Author

Adeela Afzal, Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Jose Juan Blanco-Pillado, Laura Blecha, Kimberly K. Boddy, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, Maria Charisi, Shami Chatterjee, Katerina Chatziioannou, Belinda D. Cheeseboro, Siyuan Chen, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Curt J. Cutler, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Heling Deng, Timothy Dolch, Brendan Drachler, Richard von Eckardstein, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Lydia Guertin, Kayhan Gültekin, Jeffrey S. Hazboun, Sophie Hourihane, Kristina Islo, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Vincent S. H. Lee, Natalia Lewandowska, Rafael R. Lino dos Santos, Tyson B. Littenberg, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Jonathan Nay, Priyamvada Natarajan, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Tobias Schröder, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Peter Stratmann, Jerry P. Sun, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Tanner Trickle, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sonali Verma, Sarah J. Vigeland, Haley M. Wahl, Qiaohong Wang, Caitlin A. Witt, David Wright, Olivia Young, Kathryn M. Zurek, and The NANOGrav Collaboration

Subjects
Gravitational waves, Cosmology, Particle astrophysics, Gravitational wave sources, Astrophysics, QB460-466
Abstract

The 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations of this signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, cosmic strings, and domain walls. We find that, with the exception of stable cosmic strings of field theory origin, all these models can reproduce the observed signal. When compared to the standard interpretation in terms of inspiraling supermassive black hole binaries (SMBHBs), many cosmological models seem to provide a better fit resulting in Bayes factors in the range from 10 to 100. However, these results strongly depend on modeling assumptions about the cosmic SMBHB population and, at this stage, should not be regarded as evidence for new physics. Furthermore, we identify excluded parameter regions where the predicted GW signal from cosmological sources significantly exceeds the NANOGrav signal. These parameter constraints are independent of the origin of the NANOGrav signal and illustrate how pulsar timing data provide a new way to constrain the parameter space of these models. Finally, we search for deterministic signals produced by models of ultralight dark matter (ULDM) and dark matter substructures in the Milky Way. We find no evidence for either of these signals and thus report updated constraints on these models. In the case of ULDM, these constraints outperform torsion balance and atomic clock constraints for ULDM coupled to electrons, muons, or gluons.

Published
2023
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13. How to Detect an Astrophysical Nanohertz Gravitational Wave Background

Author

Bence Bécsy, Neil J. Cornish, Patrick M. Meyers, Luke Zoltan Kelley, Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Katerina Chatziioannou, Tyler Cohen, James M. Cordes, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Sophie Hourihane, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tyson B. Littenberg, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Sophia V. Sosa Fiscella, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Rutger van Haasteren, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, and Olivia Young

Subjects
Gravitational waves, Gravitational wave sources, Gravitational wave astronomy, Supermassive black holes, Astronomy data analysis, Bayesian statistics, Astrophysics, QB460-466
Abstract

Analyses of pulsar timing data have provided evidence for a stochastic gravitational wave background in the nanohertz frequency band. The most plausible source of this background is the superposition of signals from millions of supermassive black hole binaries. The standard statistical techniques used to search for this background and assess its significance make several simplifying assumptions, namely (i) Gaussianity, (ii) isotropy, and most often, (iii) a power-law spectrum. However, a stochastic background from a finite collection of binaries does not exactly satisfy any of these assumptions. To understand the effect of these assumptions, we test standard analysis techniques on a large collection of realistic simulated data sets. The data-set length, observing schedule, and noise levels were chosen to emulate the NANOGrav 15 yr data set. Simulated signals from millions of binaries drawn from models based on the Illustris cosmological hydrodynamical simulation were added to the data. We find that the standard statistical methods perform remarkably well on these simulated data sets, even though their fundamental assumptions are not strictly met. They are able to achieve a confident detection of the background. However, even for a fixed set of astrophysical parameters, different realizations of the universe result in a large variance in the significance and recovered parameters of the background. We also find that the presence of loud individual binaries can bias the spectral recovery of the background if we do not account for them.

Published
2023
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14. Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors

Author

John G. Baker, Shane L. Larson, Jonathan R. Gair, and Michele Vallisneri

Subjects
data analysis, black holes, general relativity, gravitation, eLISA, LISA, gravitational waves, Atomic physics. Constitution and properties of matter, QC170-197
Abstract

We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ∼ 10^{-5} – 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.

Published
2013
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16. The NANOGrav 11yr Data Set: Limits on Supermassive Black Hole Binaries in Galaxies within 500 Mpc

Author

Zaven Arzoumanian, Paul T. Baker, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Bence Bécsy, Maria Charisi, Shami Chatterjee, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Rodney D. Elliott, Justin A. Ellis, Elizabeth C. Ferrara, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A. Gentile, Deborah C. Good, Jeffrey S. Hazboun, Kristina Islo, Ross J. Jennings, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Michael T. Lam, T. Joseph W. Lazio, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, David J. Nice, Timothy T. Pennucci, Nihan S. Pol, Scott M. Ransom, Paul S. Ray, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Joseph K. Swiggum, Stephen R. Taylor, Michele Vallisneri, Sarah J. Vigeland, and Caitlin A. Witt

Subjects
Astrophysics, Astronomy
Abstract

Supermassive black hole binaries (SMBHBs) should form frequently in galactic nuclei as a result of galaxy mergers. At subparsec separations, binaries become strong sources of low-frequency gravitational waves (GWs), targeted by Pulsar Timing Arrays. We used recent upper limits on continuous GWs from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 11 yr data set to place constraints on putative SMBHBs in nearby massive galaxies. We compiled a comprehensive catalog of ∼44,000 galaxies in the local universe (up to redshift ∼0.05) and populated them with hypothetical binaries, assuming that the total mass of the binary is equal to the SMBH mass derived from global scaling relations. Assuming circular equal-mass binaries emitting at NANOGrav's most sensitive frequency of 8 nHz, we found that 216 galaxies are within NANOGrav's sensitivity volume. We ranked the potential SMBHBs based on GW detectability by calculating the total signal-to-noise ratio such binaries would induce within the NANOGrav array. We placed constraints on the chirp mass and mass ratio of the 216 hypothetical binaries. For 19 galaxies, only very unequal-mass binaries are allowed, with the mass of the secondary less than 10% that of the primary, roughly comparable to constraints on an SMBHB in the Milky Way. However, we demonstrated that the (typically large) uncertainties in the mass measurements can weaken the upper limits on the chirp mass. Additionally, we were able to exclude binaries delivered by major mergers (mass ratio of at least 1/4) for several of these galaxies. We also derived the first limit on the density of binaries delivered by major mergers purely based on GW data.

Published
2021
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17. Astrophysics Milestones for Pulsar Timing Array Gravitational-wave Detection

Author

Nihan S. Pol, Stephen R. Taylor, Luke Zoltan Kelley, Sarah J. Vigeland, Joseph Simon, Siyuan Chen, Zaven Arzoumanian, Paul T. Baker, Bence Bécsy, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Shami Chatterjee, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Nathan Garver-Daniels, Deborah C. Good, Jeffrey S. Hazboun, Ross J. Jennings, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Joey Shapiro Key, Michael T. Lam, T. Joseph W. Lazio, Jing Luo, Ryan S. Lynch, Dustin R. Madison, Alexander McEwen, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, David J. Nice, Timothy T. Pennucci, Scott M. Ransom, Paul S. Ray, Brent J. Shapiro-Albert, Xavier Siemens, Ingrid H. Stairs, Daniel R. Stinebring, Joseph K. Swiggum, Michele Vallisneri, Haley Wahl, and Caitlin A. Witt

Subjects
Astrophysics, Physics Of Elementary Particles And Fields
Abstract

The NANOGrav Collaboration reported strong Bayesian evidence for a common-spectrum stochastic process in its12.5 yr pulsar timing array data set, with median characteristic strain amplitude at periods of a year of A(yr) = 1.92(+0.75,-0.55) x 10^(-15). However, evidence for the quadrupolar Hellings & Downs interpulsar correlations, which are characteristic of gravitational-wave signals, was not yet significant. We emulate and extend the NANOGrav data set, injecting a wide range of stochastic gravitational-wave background(GWB)signals that encompass a variety of amplitudes and spectral shapes, and quantify three key milestones.(I)Given the amplitude measured in the 12.5 yr analysis and assuming this signal is a GWB, we expect to accumulate robust evidence of an interpulsar-correlated GWB signal with 15–17 yr of data, i.e., an additional 2–5 yr from the 12.5 yr data set.(II)At the initial detection, we expect a fractional uncertainty of 40% on the power-law strain spectrum slope, which is sufficient to distinguish a GWB of supermassive black hole binary origin from some models predicting more exotic origins.(III)Similarly, the measured GWB amplitude will have an uncertainty of 44% upon initial detection, allowing us to arbitrate between some population models of supermassive black hole binaries. In addition, power-law models are distinguishable from those having low-frequency spectral turnovers once 20 yr of data are reached. Even though our study is based on the NANOGrav data, we also derive relations that allow for a generalization to other pulsar timing array data sets. Most notably, by combining the data of individual arrays into the International Pulsar Timing Array, all of these milestones can be reached significantly earlier.

Published
2021
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18. Multimessenger Gravitational-wave Searches with Pulsar Timing Arrays: Application to 3C 66B Using the NANOGrav 11-year Data Set

Author

Zaven Arzoumanian, Paul T Baker, Adam Brazier, Paul R Brook, Sarah Burke-Spolaor, Bence Becsy, Maria Charisi, Shami Chatterjee, James M Cordes, Neil J Cornish, Fronefield Crawford, H Thankful Cromartie, Kathryn Crowter, Megan E DeCesar, Paul B Demorest, Timothy Dolch, Rodney D Elliott, Justin A Ellis, Robert D Ferdman, Elizabeth C Ferrara, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A Gentile, Deborah C Good, Jeffrey S Hazboun, Kristina Islo, Ross J Jennings, Megan L Jones, Andrew R Kaiser, David L Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Michael T Lam, T Joseph W Lazio, Lina Levin, Jing Luo, Ryan S Lynch, Dustin R Madison, Maura A McLaughlin, Chiara M F Mingarelli, Cherry Ng, David J Nice, Timothy T Pennucci, Nihan S Pol, Scott M Ransom, Paul S Ray, Brent J Shapiro-Albert, Xavier Siemens, Joseph Simon, Renee Spiewak, Ingrid H Stairs, Daniel R Stinebring, Kevin Stovall, Joseph K Swiggum, Stephen R Taylor, Michele Vallisneri, Sarah J Vigeland, Caitlin A Witt, and Weiwei Zhu

Subjects
Astronomy
Abstract

When galaxies merge, the supermassive black holes in their centers may form binaries and emit low-frequency gravitational radiation in the process. In this paper, we consider the galaxy 3C 66B, which was used as the target of the first multimessenger search for gravitational waves. Due to the observed periodicities present in the photometric and astrometric data of the source, it has been theorized to contain a supermassive black hole binary. Its apparent 1.05-year orbital period would place the gravitational-wave emission directly in the pulsar timing band. Since the first pulsar timing array study of 3C 66B, revised models of the source have been published, and timing array sensitivities and techniques have improved dramatically. With these advances, we further constrain the chirp mass of the potential supermassive black hole binary in 3C 66B to less than (1.65±0.02)×109Me using data from the NANOGrav 11-year data set. This upper limit provides a factor of 1.6 improvement over previous limits and a factor of 4.3 over the first search done. Nevertheless, the most recent orbital model for the source is still consistent with our limit from pulsar timing array data. In addition, we are able to quantify the improvement made by the inclusion of source properties gleaned from electromagnetic data over “blind” pulsar timing array searches. With these methods, it is apparent that it is not necessary to obtain exact a priori knowledge of the period of a binary to gain meaningful astrophysical inferences.

Published
2020
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20. Accurate characterization of the stochastic gravitational-wave background with pulsar timing arrays by likelihood reweighting

Author

Sophie Hourihane, Patrick Meyers, Aaron Johnson, Katerina Chatziioannou, and Michele Vallisneri

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology
Abstract

An isotropic stochastic background of nanohertz gravitational waves creates excess residual power in pulsar-timing-array datasets, with characteristic inter-pulsar correlations described by the Hellings-Downs function. These correlations appear as nondiagonal terms in the noise covariance matrix, which must be inverted to obtain the pulsar-timing-array likelihood. Searches for the stochastic background, which require many likelihood evaluations, are therefore quite computationally expensive. We propose a more efficient method: we first compute approximate posteriors by ignoring cross correlations, and then reweight them to exact posteriors via importance sampling. We show that this technique results in accurate posteriors and marginal likelihood ratios, because the approximate and exact posteriors are similar, which makes reweighting especially accurate. The Bayes ratio between the marginal likelihoods of the exact and approximate models, commonly used as a detection statistic, is also estimated reliably by our method, up to ratios of at least $10^6$., 10 pages, 5 figures

Published
2023

22. Assessing the data-analysis impact of LISA orbit approximations using a GPU-accelerated response model

Author

Michael L. Katz, Jean-Baptiste Bayle, Alvin J. K. Chua, and Michele Vallisneri

Subjects
FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), General Relativity and Quantum Cosmology
Abstract

The analysis of gravitational wave (GW) datasets is based on the comparison of measured time series with theoretical templates of the detector's response to a variety of source parameters. For LISA, the main scientific observables will be the so-called time-delay interferometry (TDI) combinations, which suppress the otherwise overwhelming laser noise. Computing the TDI response to GW involves projecting the GW polarizations onto the LISA constellation arms, and then combining projections delayed by a multiple of the light propagation time along the arms. Both computations are difficult to perform efficiently for generic LISA orbits and GW signals. Various approximations are currently used in practice, e.g., assuming constant and equal armlengths, which yields analytical TDI expressions. In this article, we present 'fastlisaresponse', a new efficient GPU-accelerated code that implements the generic TDI response to GWs in the time domain. We use it to characterize the parameter-estimation bias incurred by analyzing loud Galactic-binary signals using the equal-armlength approximation. We conclude that equal-armlength parameter-estimation codes should be upgraded to the generic response if they are to achieve optimal accuracy for high (but reasonable) SNR sources within the actual LISA data., Comment: 15 pages, 7 figures, 2 tables

Published
2022
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25. Bayesian cross validation for gravitational-wave searches in pulsar-timing array data

Author

Michele Vallisneri, Haochen Wang, and Stephen Taylor

Subjects
Physics, Bayesian probability, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), General Relativity and Quantum Cosmology (gr-qc), Overfitting, Bayesian inference, 01 natural sciences, General Relativity and Quantum Cosmology, Cross-validation, Data set, Space and Planetary Science, 0103 physical sciences, Prior probability, Astrophysics - Instrumentation and Methods for Astrophysics, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Algorithm, Test data
Abstract

Gravitational-wave data analysis demands sophisticated statistical noise models in a bid to extract highly obscured signals from data. In Bayesian model comparison, we choose among a landscape of models by comparing their marginal likelihoods. However, this computation is numerically fraught and can be sensitive to arbitrary choices in the specification of parameter priors. In Bayesian cross validation, we characterize the fit and predictive power of a model by computing the Bayesian posterior of its parameters in a training dataset, and then use that posterior to compute the averaged likelihood of a different testing dataset. The resulting cross-validation scores are straightforward to compute; they are insensitive to prior tuning; and they penalize unnecessarily complex models that overfit the training data at the expense of predictive performance. In this article, we discuss cross validation in the context of pulsar-timing-array data analysis, and we exemplify its application to simulated pulsar data (where it successfully selects the correct spectral index of a stochastic gravitational-wave background), and to a pulsar dataset from the NANOGrav 11-year release (where it convincingly favors a model that represents a transient feature in the interstellar medium). We argue that cross validation offers a promising alternative to Bayesian model comparison, and we discuss its use for gravitational-wave detection, by selecting or refuting models that include a gravitational-wave component., Comment: 7 pages, 4 figures. Submitted to MNRAS

Published
2019
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26. Erratum: 'Searches for Continuous Gravitational Waves from Nine Young Supernova Remnants' (2015, ApJ, 813, 39) *

Author

G. L. Mansell, Piotr Jaranowski, Florent Robinet, P. G. Murray, V. Dattilo, Tejinder Kaur, Edwin J. Son, Fabien Kéfélian, J. H. Hough, Stefan Hild, Y. Ma, Adam A. Libson, Douglas R. Cook, Michele Zanolin, S. H. Huttner, N. A. Robertson, A. Brillet, T. J. Massinger, V. Kalogera, C. Padilla, P. J. Sutton, C. C. Wipf, Alex B. Nielsen, J. H. Romie, Charlotte Bond, S. A. Usman, G. D. Hammond, C. Belczynski, M. A. Barton, Andrew Melatos, M. Lorenzini, A. Masserot, S. E. Hollitt, Alberto Vecchio, L. Prokhorov, R. Douglas, F. J. Raab, J. G. Bartlett, Márton Tápai, David Jonathan Hofman, L. R. Cominsky, G. McIntyre, Leo Singer, Sascha Husa, Meng Wang, D.B. DeBra, Mark Hannam, Samuel Deléglise, Will M. Farr, R. Gustafson, M. P. Thirugnanasambandam, Liam Cunningham, J. L. Willis, Nancy Aggarwal, M. R. Smith, M. Edwards, A. C. Lin, Tobias Eberle, Francesco Pannarale, A. Rocchi, Jong H. Chow, A. Pasqualetti, S. Mirshekari, F. Garufi, Howard Pan, Aaron Buikema, J. Macarthur, Maria Ilaria Del Principe, M. Tse, Máté Nagy, M. Agathos, S. R. Morriss, P. M. Meyers, Paul J. Groot, S. Raja, S. E. Strigin, Namjun Kim, C. Krueger, I. Dave, B. Hughey, D. M. Macleod, M. Barbet, M. Meinders, D. B. Kelley, E. Cesarini, Joseph Gleason, V. Fafone, X. Guo, K. Siellez, E. J. King, Zhihui Du, F. Mezzani, G. M. Keiser, S. Márka, J. Zweizig, Walter Winkler, K. A. Thorne, M. J. Cowart, S. E. Gossan, A. S. Markosyan, A. Mytidis, Harald Lück, B. L. Swinkels, Timothy A Welborn, John Veitch, M. Cho, Kendall Ackley, R. K. Nayak, D. Moraru, A. Gennai, S. S. Eikenberry, Fabio Marchesoni, P. Hello, J. R. Leong, S. C. McGuire, N. A. Gordon, Gianpietro Cagnoli, F. Vetrano, S. E. Dwyer, David Keitel, G. Mendell, M. MacInnis, P. Rapagnani, Alexander Khalaidovski, K. Haris, Ilya Mandel, D. Barker, Gerhard Heinzel, Suvadeep Bose, V. Predoi, Virginio Sannibale, David E. McClelland, P. Couvares, Benno Willke, Rosa Poggiani, C. Affeldt, Sebastian Steinlechner, D. Passuello, F. Magaña-Sandoval, Kyungmin Kim, B. O'Reilly, Z. Márka, S. Mitra, Ajay Kumar, G. Quiroga, Eric Oelker, J. Bergman, P. J. Veitch, L. P. Dartez, J. Ming, A. K. Poteomkin, Tyson Littenberg, M. Korobko, I. Maksimovic, Alberto Gatto, Chris Pankow, C. C. Arceneaux, S. Farinon, C. J. Bell, Soumya D. Mohanty, R. L. Ward, G. Hemming, Hyun Lee, B. Mours, A. Chiummo, R. Taylor, H. J. Bulten, Christian D. Ott, Heinz-Bernd Eggenstein, C. L. Mueller, C. Osthelder, M. Ducrot, D. O. Bridges, Rebecca Fisher, Badri Krishnan, H. Kaufer, P. Raffai, M. M. Hanke, L. K. Nuttall, K. Mason, S. B. Anderson, S. M. Koehlenbeck, A. Ain, Tristan Briant, T. P. Bodiya, S. Walsh, Q. Chu, C. Maglione, Grant David Meadors, C. Buy, Jeffery Kline, T. Huynh-Dinh, E. C. Ferreira, Sanjeev Dhurandhar, C. Messenger, Peter Aufmuth, F. Carbognani, B. Behnke, Luca Gammaitoni, E. O. Lebigot, Peter Wessels, Ruslan Vaulin, Bala R. Iyer, G. M. Harry, A. R. Wade, G. Kuehn, K. Venkateswara, J. Hanks, Prayush Kumar, R. M. Martin, V. Dolique, Kieran Craig, Alessandra Buonanno, Jiayi Qin, A. Singer, F. Jiménez-Forteza, J. B. Kanner, Oscar Reula, G. P. Newton, M. Fyffe, J. S. Kissel, N. Letendre, P. Thomas, A. M. Sintes, C. Baune, S. McCormick, M. Branchesi, J. C. Batch, C. M. Mow-Lowry, M. Boer, Marc Favata, L. E. Wade, J. N. Marx, László Á. Gergely, Yuri Levin, Sergey P. Vyatchanin, A. Idrisy, Xavier Siemens, Fumiko Kawazoe, A. Conte, Roger Jones, V. J. Roma, W. D. Vousden, Gabriela Gonzalez, C. Aulbert, R. Cavalieri, D. Ugolini, K. A. Hodge, F. Marion, E. Katsavounidis, N. Leroy, K. Nedkova, Laura Cadonati, D. D. Brown, Chandra Kant Mishra, R. Bhandare, N. van Bakel, D. Rosińska, J. O'Dell, Christopher M. Biwer, L. Matone, T. P. Downes, Si Xie, Robert Stone, H. Radkins, R. Chakraborty, A. Di Virgilio, S. Frasca, S. S. Premachandra, A. Viceré, D. Simakov, Yi Chen, M. Pedraza, A. Basti, M. Kasprzack, V. Re, E. A. Houston, Bruce Gendre, B. E. Aylott, Reinhard Prix, X. F. Wang, K. Kawabe, S. M. Aston, H. Fehrmann, J.-P. Coulon, M. Lormand, G. Debreczeni, M. Brinkmann, Z. Frei, Stefaan Franco, Maria Alessandra Papa, B. F. Whiting, Michael W. Coughlin, Sung-Po Chao, E. Schreiber, David Coward, M. J. Lubinski, A. R. Williamson, C. Tomlinson, M. Mageswaran, J. D. Lough, Rana X. Adhikari, F. Cavalier, Soma Mukherjee, Drew Keppel, Mikhail L. Gorodetsky, Sheon Chua, C. J. Guido, V. Sequino, Robinjeet Singh, R. De Rosa, S. Chung, I. Nardecchia, M. E. Normandin, Jonathan F. Stebbins, T. Etzel, R. Bonnand, H. P. Daveloza, L. Bonelli, J.-D. Fournier, J. Aasi, Jade Powell, V. Mangano, Andreas Freise, Vincenzo Pierro, Paul D. Lasky, Philip F. Hopkins, Carl Blair, Archana Pai, M. Yvert, Fan Zhang, C. S. Unnikrishnan, Carlos Cepeda, M. Prijatelj, P. J. King, T. Dal Canton, J. Warner, R. Passaquieti, M. Huynh, Teviet Creighton, F. Paoletti, P. Ruggi, Xing-Jiang Zhu, B. Machenschalk, Kevin M. McLin, Matthew Pitkin, J. T. Whelan, H. R. Paris, Collin Capano, S. G. Crowder, Robert J. McCarthy, M. Wade, Linqing Wen, G. Kang, Ryan DeRosa, I. Fiori, Christian Gräf, M. Jacobson, A. Mullavey, M. Granata, Satya Mohapatra, Curt Cutler, William Yam, L. Wallace, F. Donovan, M. Razzano, J. Poeld, A. Królak, R. Frey, David H. Reitze, A. Nitz, B. C. Pant, Yi-Ming Hu, C. Van Den Broeck, Jessica Steinlechner, Hee-Suk Cho, M. Damjanic, L. Kuo, H. Yamamoto, Minchuan Zhou, F. Martelli, J. R. Sanders, G. A. Prodi, S. Fairhurst, J. Prasad, M. Born, I. Di Palma, Vuk Mandic, Vladimir B. Braginsky, H. Vahlbruch, R. DeSalvo, Sourav Ghosh, Imre Bartos, J. Eichholz, S. Fuentes-Tapia, Richard O'Shaughnessy, B. Barr, Alessandra Corsi, Malik Rakhmanov, J. Worden, Gleb Romanov, Sweta Shah, K. E. Ramirez, L. Rei, Chad Hanna, B. Shapiro, M. Heurs, Gijs Nelemans, E. D. Hall, L. Williams, D. Meacher, A. Rüdiger, N. M. Brown, Reed Essick, S. Caride, C. Wilkinson, K. Mailand, O. V. Palashov, Sean T. McWilliams, F. Piergiovanni, Lindy Blackburn, Steven Bloemen, Jonathan R. Gair, Riccardo Bassiri, Qi Fang, A. K. Zadrożny, V. Boschi, K. Riles, Th. S. Bauer, V. Quetschke, Bangalore Suryanarayana Sathyaprakash, K. Holt, Chunglee Kim, A. L. Stuver, Benjamin William Allen, S. Kandhasamy, G. Szeifert, M. van Beuzekom, Y. Ji, B. Sorazu, Ryan Lynch, Matthew Abernathy, Martin M. Fejer, Kasem Mossavi, J. R. Smith, V. Sandberg, R. Bork, J. Logue, R. Mittleman, J. Y. Vinet, H. Middleton, Nelson Christensen, P. T. Baker, D. S. Rabeling, M. Neri, Q. Yang, E. J. Daw, J. A. Giaime, V. Lockett, N. A. Lockerbie, Blake Moore, K. E. Gushwa, E. Maros, D. Amariutei, T. Nash, P. Leaci, A. Colla, M. Davier, M. Factourovich, Roland Schilling, Y. M. Kim, Rocco Romano, J. S. Key, Paolo Addesso, K. D. Giardina, A. Kutynia, Markus A. Wimmer, M. Weinert, F. Fidecaro, John D. Scott, G. M. Guidi, D. C. Coyne, M. Fays, B. M. Levine, A. Di Lieto, S. M. Scott, Andrea Chincarini, J. Betzwieser, D. L. Kinzel, K. Izumi, R. A. Mercer, D. Steinmeyer, Jordan Camp, L. Naticchioni, D. Feldbaum, Karsten Danzmann, Thomas Dent, S. J. Chamberlin, M. Vasúth, G. Dojcinoski, G. Serna, Simon Stevenson, S. A. Pai, D. Nolting, Antoine Heidmann, Swetha Bhagwat, Hua Wang, M. Colombini, Salvatore Vitale, Kipp Cannon, M. Steinke, F. Travasso, M. Punturo, T. Z. Summerscales, Michał Bejger, Shane L. Larson, Leopoldo Milano, Jonathan Cripe, W. Katzman, A. Moggi, A. Effler, R. S. Ottens, A. L. Urban, Vladimir Dergachev, Kazuhiro Agatsuma, M. A. Bizouard, Xi-Long Fan, S. P. Tarabrin, P. Ajith, S. T. Countryman, D. B. Tanner, H. Overmier, Jesper Munch, N. Mazumder, F. Nocera, J. C. Barayoga, D. J. White, Hartmut Grote, T. Denker, G. Losurdo, F. Frasconi, A. Perreca, Kevin M. Ryan, G. Gemme, M. Drago, C. Zhao, V. Necula, I. Santiago-Prieto, Surabhi Sachdev, Ettore Majorana, M. De Laurentis, Christopher P. L. Berry, Andrea Taracchini, A. D. Silva, Guenakh Mitselmakher, A. F. Brooks, C-H. Lee, Slawomir Gras, V. V. Frolov, D. Schuette, Albert Lazzarini, D. Sellers, R. Flaminio, A. Pal-Singh, Sebastien Biscans, P. Ehrens, Katrin Dahl, Y.-H. Zhang, A. M. Sergeev, J. Meidam, Riccardo Sturani, P. Puppo, A. Staley, W. Ortega, F. Cleva, S. Jawahar, T. B. Edo, M. Pichot, Evan Ochsner, Z. Shao, Neil J. Cornish, B. Moe, M. Bitossi, G. Bergmann, Lionel Martellini, Odylio D. Aguiar, I. W. Martin, Matthew Evans, E. A. Huerta, Marco Aurelio Diaz, A. J. Weinstein, M. V. van der Sluys, D. Hoak, D. Sentenac, Patrick Brady, T. Prestegard, K. Kokeyama, N. D. Smith-Lefebvre, J. Calderón Bustillo, K. Wette, T. Theeg, Denis Martynov, John J. Oh, R. Goetz, László Gondán, Timothy Evans, I. Yakushin, J. J. Hacker, L. Sammut, Stanislav Babak, Tarun Souradeep, S. Doravari, R. Inta, Peter Fritschel, M. Constancio, Duncan A. Brown, S. Klimenko, Igor Neri, Rory Smith, C. Adams, J. Birch, R. J. S. Greenhalgh, Gavin Davies, D. Sigg, S. W. Ballmer, D. J. Hosken, V. Loriette, L. Pinard, E. Coccia, C. Palomba, M. C. Araya, S. Privitera, O. Puncken, M. E. Zucker, B. A. Weaver, Federico Ferrini, Francesco Salemi, M. Landry, M. S. Shahriar, R. M. Magee, L. Di Fiore, M. Tonelli, Larry R. Price, C. Lazzaro, J. G. Rollins, Michelle E. Walker, G. Moreno, Patricia Schmidt, V. Brisson, L.-W. Wei, G. Vajente, H. Dereli, S. Ast, C. M. Reed, M. Leonardi, Kip S. Thorne, E. Dominguez, E. A. Quintero, Enrico Calloni, Jessica McIver, S. D'Antonio, S. E. Zuraw, G. Traylor, Thomas Corbitt, C. A. Costa, S. Kaufer, T. Chalermsongsak, Alessandro Bertolini, M. Barsuglia, B. Sassolas, Rainer Weiss, F. Ricci, Andrew Lundgren, T. Regimbau, C. I. Torrie, W. W. Johnson, A. Grant, N. Straniero, Laleh Sadeghian, David Tshilumba, V. P. Mitrofanov, P. Bojtos, Thanh Vinh Nguyen, D. R. Ingram, David Blair, M. Saleem, W. Del Pozzo, P. F. Cohadon, L. Zhang, Trevor Sidery, H. Heitmann, D. Bersanetti, G. Tellez, J. V. van Heijningen, Joshua Yablon, John S. Lewis, Eric Thrane, Roman Schnabel, J. E. Brau, A. A. van Veggel, Efim A. Khazanov, C. Michel, G. Ballardin, Sarah Caudill, R. Quitzow-James, R. Day, M. Phelps, F. Ohme, V. B. Adya, R. Robie, F. Clara, J. S. Areeda, Z. Patrick, V. Malvezzi, Sasha Buchman, Timothy MacDonald, Carl-Johan Haster, L. Rolland, N. Indik, Fabrizio Barone, M. Mohan, N. Man, K. A. Strain, H. J. Jang, K. Haughian, I. M. Pinto, Nam-Gyu Kim, W. Z. Korth, D. Talukder, C. V. Torres, I. W. Harry, Tobias Westphal, R. Gouaty, David Jones, Marco Cavaglia, Fausto Acernese, Mi Zhang, C. Gray, G. H. Ogin, M. Mantovani, A. W. Heptonstall, Vivien Raymond, Peter R. Saulson, R. Abbott, Vaibhav Tiwari, B. C. Stephens, J. P. Zendri, A. Giazotto, P. Shawhan, I. Ferrante, D. Verkindt, P. Charlton, M. T. Hartman, V. Kringel, B. Lantz, S. Goßler, Philip Graff, I. A. Bilenko, David J. Ottaway, J. D. E. Creighton, R. M. S. Schofield, Matthew Benacquista, Benjamin J. Owen, J. F. J. van den Brand, Tomasz Bulik, M. Tacca, Richard J. Oram, Martin Hendry, François Bondu, T. Hardwick, Martin Hewitson, Junwei Cao, P. Fulda, S. E. Barclay, Tjonnie G. F. Li, Eric Howell, S. Leavey, Jon M. Miller, G. Billingsley, R. L. Savage, A. S. Bell, T. Isogai, F. Y. Khalili, Graham Woan, A. Allocca, Stuart Reid, G. Rajalakshmi, G. Valdes, Jacob Scheuer, G. Islas, T. T. Fricke, Bernard F. Schutz, Li Ju, M. Was, Daniel A. Shaddock, J. Hanson, H. Vocca, Eugeniy E. Mikhailov, Guido Mueller, G. Vedovato, D. B. Kozak, C. Vorvick, A. Sevigny, David Murphy, G. Mazzolo, A. L. Lombardi, C. C. Yancey, W. G. Anderson, G. Cella, Giacomo Ciani, B. P. Abbott, E. K. Gustafson, S. Vass, R. Vincent-Finley, R. Coyne, Fabrice Matichard, W. Kells, J. Le, T. Sadecki, S. Grunewald, J. C. Isler, D. H. Shoemaker, Kenneth G. Libbrecht, A. Cumming, E. Genin, F. Baldaccini, A. J. Miller, M. J. Hart, A. M. Gretarsson, J. K. Blackburn, A. Sawadsky, E. Chassande-Mottin, Sheila Rowan, M. Pürrer, Todd Adams, Jan Harms, A. S. Sengupta, Viswanath Bavigadda, Samaya Nissanke, D. Buskulic, E. Cuoco, A. Post, S. Meshkov, Seog Oh, B. J. J. Slagmolen, Margaret Millhouse, S. G. Gaonkar, Haixing Miao, S. L. Danilishin, G. Bogaert, M. Shaltev, O. Bock, István Rácz, K. L. Dooley, Lisa Barsotti, R. J. G. Jonker, V. Kondrashov, A. Alemic, Y. Minenkov, H. Wittel, Matthew Heintze, T. M. C. Abbott, J. C. Driggers, Michael Thomas, Koji Arai, Roy Williams, G. Pillant, I. Kowalska, A. Pele, Nergis Mavalvala, Jerome Degallaix, B. C. Barish, John A. Clark, Ben Farr, Christophe Collette, Ho-Gyu Lee, N. Gehrels, T. Vo, Marek Szczepanczyk, C. Bradaschia, P. Oppermann, Michele Vallisneri, Ik Siong Heng, S. Steplewski, P. Astone, Larne Pekowsky, E. Goetz, S. Penn, and (Astro)-Particles Physics

Subjects
Physics, Supernova, Space and Planetary Science, Gravitational wave, Astronomy, Astronomy and Astrophysics, Limit (mathematics), Astrophysics, Vela, Table (information)
Abstract

Equation (7) of the published article (Aasi et al. 2015) is in error; it should read (Equation presented). The upper limits on ò presented in the published article are unaffected by this error. Equation (8) of the published article is in error; it should read (Equation presented) The upper limits on α presented in Figure 3 and Table 4 of the published article were computed incorrectly. The revised Figure 3 (bottom) shows the corrected upper limits on α for the G266.2-1.2 (Vela Jr.) wide search. The revised Table 4 is provided here. The correct lowest upper limit on α (quoted in the Abstract of the published article) is 3 × 10-6. Figure 4 shows the incorrect and corrected upper limits on α for the G266.2-1.2 (Vela Jr.) wide search, which have been surpassed by upper limits from Abbott et al. (2019).

Published
2021
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27. The NANOGrav 12.5-year Data Set: Search for Non-Einsteinian Polarization Modes in the Gravitational-wave Background

Author

Zaven Arzoumanian, Paul T. Baker, Harsha Blumer, Bence Bécsy, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Maria Charisi, Shami Chatterjee, Siyuan Chen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Dallas M. DeGan, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Justin A. Ellis, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A. Gentile, Deborah C. Good, Jeffrey S. Hazboun, A. Miguel Holgado, Kristina Islo, Ross J. Jennings, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Nima Laal, Michael T. Lam, T. Joseph W. Lazio, Duncan R. Lorimer, Tingting Liu, Jing Luo, Ryan S. Lynch, Dustin R. Madison, Alexander McEwen, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, David J. Nice, Ken D. Olum, Timothy T. Pennucci, Nihan S. Pol, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Jerry P. Sun, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), and NANOGrav

Subjects
noise, family, gravitation: model, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), power spectrum, 01 natural sciences, Bayesian, General Relativity and Quantum Cosmology, 0103 physical sciences, 010303 astronomy & astrophysics, pulsar, High Energy Astrophysical Phenomena (astro-ph.HE), polarization, 010308 nuclear & particles physics, gravitational radiation: background, Astronomy and Astrophysics, NANOGrav, solar system, Astrophysics - Astrophysics of Galaxies, transverse, space-time, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), correlation, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We search NANOGrav's 12.5-year data set for evidence of a gravitational wave background (GWB) with all the spatial correlations allowed by general metric theories of gravity. We find no substantial evidence in favor of the existence of such correlations in our data. We find that scalar-transverse (ST) correlations yield signal-to-noise ratios and Bayes factors that are higher than quadrupolar (tensor transverse, TT) correlations. Specifically, we find ST correlations with a signal-to-noise ratio of 2.8 that are preferred over TT correlations (Hellings and Downs correlations) with Bayesian odds of about 20:1. However, the significance of ST correlations is reduced dramatically when we include modeling of the Solar System ephemeris systematics and/or remove pulsar J0030$+$0451 entirely from consideration. Even taking the nominal signal-to-noise ratios at face value, analyses of simulated data sets show that such values are not extremely unlikely to be observed in cases where only the usual TT modes are present in the GWB. In the absence of a detection of any polarization mode of gravity, we place upper limits on their amplitudes for a spectral index of $\gamma = 5$ and a reference frequency of $f_\text{yr} = 1 \text{yr}^{-1}$. Among the upper limits for eight general families of metric theories of gravity, we find the values of $A^{95\%}_{TT} = (9.7 \pm 0.4)\times 10^{-16}$ and $A^{95\%}_{ST} = (1.4 \pm 0.03)\times 10^{-15}$ for the family of metric spacetime theories that contain both TT and ST modes., Comment: 24 pages, 18 figures, 3 appendices. Please send any comments/questions to Nima Laal (laaln@oregonstate.edu)

Published
2021
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28. Time-delay interferometry without delays

Author

Michele Vallisneri, Antoine Petiteau, Jean-Baptiste Bayle, Stanislav Babak, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Phase (waves), detector: noise, 01 natural sciences, law.invention, cosmic rays, Observatory, law, wave: propagation, 0103 physical sciences, Experiments in gravity, Limit (mathematics), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Linear combination, Representation (mathematics), 010303 astronomy & astrophysics, orbit, Physics, time delay: interferometer, LISA, 010308 nuclear & particles physics, gravitational radiation, Observable, Laser, gravitational radiation detector, laser, Interferometry, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], time dependence, Algorithm, cosmology
Abstract

International audience; The space-based gravitational-wave observatory LISA relies on a form of synthetic interferometry (time-delay interferometry, or TDI) where the otherwise overwhelming laser phase noise is canceled by linear combinations of appropriately delayed phase measurements. These observables grow in length and complexity as the realistic features of the LISA orbits are taken into account. In this paper we outline an implicit formulation of TDI where we write the LISA likelihood directly in terms of the basic phase measurements, and we marginalize over the laser phase noises in the limit of infinite laser-noise variance. Equivalently, we rely on TDI observables that are defined numerically (rather than algebraically) from a discrete-filter representation of the laser propagation delays. Our method generalizes to any time dependence of the armlengths; it simplifies the modeling of gravitational-wave signals; and it allows a straightforward treatment of data gaps and missing measurements.

Published
2021
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29. Astrophysics Milestones for Pulsar Timing Array Gravitational-wave Detection

Author

Paul R. Brook, Megan E. Decesar, David J. Nice, Chiara M. F. Mingarelli, Sarah Burke-Spolaor, Timothy T. Pennucci, H. Thankful Cromartie, Brent J. Shapiro-Albert, Nathan Garver-Daniels, Timothy Dolch, Daniel R. Stinebring, Paul Demorest, Alexander McEwen, Ryan S. Lynch, Siyuan Chen, James M. Cordes, Scott M. Ransom, Paul T. Baker, Luke Zoltan Kelley, Ingrid H. Stairs, Megan L. Jones, Neil J. Cornish, Ross J. Jennings, Paul S. Ray, Haley M. Wahl, Adam Brazier, Joseph Simon, William Fiore, Jeffrey S. Hazboun, Joseph K. Swiggum, T. Joseph W. Lazio, Cherry Ng, Joey Shapiro Key, Elizabeth C. Ferrara, Michael T. Lam, Xavier Siemens, Jing Luo, D. R. Madison, Deborah C. Good, Maura McLaughlin, Sarah J. Vigeland, B. Bécsy, Michele Vallisneri, Zaven Arzoumanian, David L. Kaplan, Caitlin A. Witt, Fronefield Crawford, Shami Chatterjee, Emmanuel Fonseca, Stephen Taylor, Andrew R. Kaiser, Nihan Pol, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), and NANOGrav

Subjects
010504 meteorology & atmospheric sciences, gravitational radiation: stochastic, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, 01 natural sciences, Gravitational-wave astronomy, Bayesian, General Relativity and Quantum Cosmology, Gravitational wave background, Pulsar timing array, Pulsar, Millisecond pulsar, 0103 physical sciences, black hole, gravitational radiation: spectrum, cosmic string, 010303 astronomy & astrophysics, spectrum: slope, 0105 earth and related environmental sciences, pulsar, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Gravitational wave, gravitational radiation: background, Astronomy and Astrophysics, NANOGrav, Astrophysics - Astrophysics of Galaxies, Cosmic string, Amplitude, black hole: binary, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), correlation, fractional, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], spectral, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The NANOGrav Collaboration reported strong Bayesian evidence for a common-spectrum stochastic process in its 12.5-yr pulsar timing array dataset, with median characteristic strain amplitude at periods of a year of $A_{\rm yr} = 1.92^{+0.75}_{-0.55} \times 10^{-15}$. However, evidence for the quadrupolar Hellings \& Downs interpulsar correlations, which are characteristic of gravitational wave signals, was not yet significant. We emulate and extend the NANOGrav dataset, injecting a wide range of stochastic gravitational wave background (GWB) signals that encompass a variety of amplitudes and spectral shapes, and quantify three key milestones: (I) Given the amplitude measured in the 12.5 yr analysis and assuming this signal is a GWB, we expect to accumulate robust evidence of an interpulsar-correlated GWB signal with 15--17 yrs of data, i.e., an additional 2--5 yrs from the 12.5 yr dataset; (II) At the initial detection, we expect a fractional uncertainty of $40\%$ on the power-law strain spectrum slope, which is sufficient to distinguish a GWB of supermassive black-hole binary origin from some models predicting more exotic origins;(III) Similarly, the measured GWB amplitude will have an uncertainty of $44\%$ upon initial detection, allowing us to arbitrate between some population models of supermassive black-hole binaries. In addition, power-law models are distinguishable from those having low-frequency spectral turnovers once 20~yrs of data are reached. Even though our study is based on the NANOGrav data, we also derive relations that allow for a generalization to other pulsar-timing array datasets. Most notably, by combining the data of individual arrays into the International Pulsar Timing Array, all of these milestones can be reached significantly earlier., 15 pages, 7 figures

Published
2021
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30. Multimessenger gravitational-wave searches with pulsar timing arrays: Application to 3C 66B using the NANOGrav 11-year data set

Author

Maria Charisi, Ryan S. Lynch, Daniel R. Stinebring, David J. Nice, Timothy Dolch, Justin A. Ellis, Paul Demorest, Weiwei Zhu, Dustin R. Madison, Jing Luo, Peter A. Gentile, Jeffrey S. Hazboun, Maura McLaughlin, K. Islo, Nathan Garver-Daniels, Scott M. Ransom, Rodney D. Elliott, Nihan Pol, Stephen Taylor, Ingrid H. Stairs, H. Thankful Cromartie, Fronefield Crawford, Michael T. Lam, Timothy T. Pennucci, Joseph Simon, Michele Vallisneri, James M. Cordes, Luke Zoltan Kelley, Andrew R. Kaiser, Shami Chatterjee, Kevin Stovall, Joseph K. Swiggum, David L. Kaplan, Cherry Ng, Ross J. Jennings, Elizabeth C. Ferrara, Paul R. Brook, Xavier Siemens, Chiara M. F. Mingarelli, Joey Shapiro Key, Sarah Burke-Spolaor, Adam Brazier, Megan E. DeCesar, Caitlin A. Witt, Emmanuel Fonseca, Brent J. Shapiro-Albert, Paul T. Baker, Neil J. Cornish, Bence Bécsy, Kathryn Crowter, Megan L. Jones, Paul S. Ray, Renée Spiewak, Deborah C. Good, Zaven Arzoumanian, Lina Levin, T. Joseph W. Lazio, Robert D. Ferdman, and Sarah J. Vigeland

Subjects
Physics, Supermassive black hole, Active galactic nucleus, 010504 meteorology & atmospheric sciences, Gravitational wave, Astrophysics::High Energy Astrophysical Phenomena, Binary number, Astronomy and Astrophysics, Astrophysics, Orbital period, 01 natural sciences, Galaxy, Pulsar timing array, Pulsar, Space and Planetary Science, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

When galaxies merge, the supermassive black holes in their centers may form binaries and emit low-frequency gravitational radiation in the process. In this paper, we consider the galaxy 3C 66B, which was used as the target of the first multimessenger search for gravitational waves. Due to the observed periodicities present in the photometric and astrometric data of the source, it has been theorized to contain a supermassive black hole binary. Its apparent 1.05-year orbital period would place the gravitational-wave emission directly in the pulsar timing band. Since the first pulsar timing array study of 3C 66B, revised models of the source have been published, and timing array sensitivities and techniques have improved dramatically. With these advances, we further constrain the chirp mass of the potential supermassive black hole binary in 3C 66B to less than (1.65 ± 0.02) × 109 M ⊙ using data from the NANOGrav 11-year data set. This upper limit provides a factor of 1.6 improvement over previous limits and a factor of 4.3 over the first search done. Nevertheless, the most recent orbital model for the source is still consistent with our limit from pulsar timing array data. In addition, we are able to quantify the improvement made by the inclusion of source properties gleaned from electromagnetic data over “blind” pulsar timing array searches. With these methods, it is apparent that it is not necessary to obtain exact a priori knowledge of the period of a binary to gain meaningful astrophysical inferences.

Published
2020

31. GipsyX/RTGx, A New Tool Set for Space Geodetic Operations and Research

Author

Mark Miller, Pascal Willis, Michael Heflin, Wenwen Lu, Michele Vallisneri, Bruce J. Haines, Dave Murphy, Angie Dorsey, Willy Bertiger, Larry Romans, Aurore Sibois, Ant Sibthorpe, Angelyn Moore, Yoaz Bar-Sever, Nate Harvey, Dan Hemberger, Paul Ries, and Béla Szilágyi

Subjects
Atmospheric Science, International Terrestrial Reference System, 010504 meteorology & atmospheric sciences, Computer science, FOS: Physical sciences, Aerospace Engineering, Precise Point Positioning, 01 natural sciences, Physics - Geophysics, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, business.industry, Satellite laser ranging, DORIS (geodesy), Astronomy and Astrophysics, Geodesy, Geophysics (physics.geo-ph), Geophysics, Space and Planetary Science, GNSS applications, Global Positioning System, General Earth and Planetary Sciences, Satellite, business, Terrestrial reference frame
Abstract

GipsyX/RTGx is the Jet Propulsion Laboratory's (JPL) next generation software package for positioning, navigation, timing, and Earth science using measurements from three geodetic techniques: Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS); with Very Long Baseline Interferometry (VLBI) under development. The software facilitates combined estimation of geodetic and geophysical parameters using a Kalman filter approach on real or simulated data in both post-processing and in real-time. The estimated parameters include station coordinates and velocities, satellite orbits and clocks, Earth orientation, ionospheric and tropospheric delays. The software is also capable of full realization of a dynamic terrestrial reference through analysis and combination of time series of ground station coordinates. We present some key aspects of its new architecture, and describe some of its major applications, including Real-time orbit determination and ephemeris predictions in the U.S. Air Force Next Generation GPS Operational Control Segment (OCX), as well as in JPL's Global Differential GPS (GDGPS) System, supporting User Range Error (URE) of $, Comment: 65 pages, 14 figures

Published
2020

32. NANOGrav 11 yr Data Set: Evolution of Gravitational-wave Background Statistics

Author

Lina Levin, Scott M. Ransom, J. E. Turner, Jing Luo, D. R. Stinebring, I. H. Stairs, D. R. Lorimer, Peter A. Gentile, E. C. Ferrara, Joseph K. Swiggum, Paul Demorest, Deborah C. Good, A. M. Holgado, Adam Brazier, D. R. Madison, Robert D. Ferdman, R. van Haasteren, Paul R. Brook, Sarah Burke-Spolaor, J. M. Cordes, H. T. Cromartie, K. Islo, M. E. DeCesar, Fronefield Crawford, Nihan Pol, M. L. Jones, Luke Zoltan Kelley, Kevin Stovall, Timothy Dolch, N. Garver-Daniels, Andrea N. Lommen, Kathryn Crowter, Caitlin A. Witt, Andrew R. Kaiser, Paul S. Ray, E. A. Huerta, Sourav Chatterjee, Paul T. Baker, Cherry Ng, G. Jones, Xavier Siemens, David L. Kaplan, Neil J. Cornish, Ross J. Jennings, Joseph Simon, Michael T. Lam, Stephen Taylor, Joey Shapiro Key, Emmanuel Fonseca, Zaven Arzoumanian, Maura McLaughlin, Michele Vallisneri, Chiara M. F. Mingarelli, T. J. W. Lazio, R. S. Lynch, Sarah J. Vigeland, Sean T. McWilliams, David J. Nice, Timothy T. Pennucci, R. Spiewak, Wenbai Zhu, Jeffrey S. Hazboun, and J. A. Ellis

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Spectral index, Supermassive black hole, 010308 nuclear & particles physics, Gravitational wave, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, General Relativity and Quantum Cosmology, Gravitational wave background, Pulsar, 13. Climate action, Space and Planetary Science, Colors of noise, Millisecond pulsar, 0103 physical sciences, Statistics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Noise (radio)
Abstract

An ensemble of inspiraling supermassive black hole binaries should produce a stochastic background of very low frequency gravitational waves. This stochastic background is predicted to be a power law, with a spectral index of -2/3, and it should be detectable by a network of precisely timed millisecond pulsars, widely distributed on the sky. This paper reports a new "time slicing" analysis of the 11-year data release from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) using 34 millisecond pulsars. Methods to flag potential "false positive" signatures are developed, including techniques to identify responsible pulsars. Mitigation strategies are then presented. We demonstrate how an incorrect noise model can lead to spurious signals, and show how independently modeling noise across 30 Fourier components, spanning NANOGrav's frequency range, effectively diagnoses and absorbs the excess power in gravitational-wave searches. This results in a nominal, and expected, progression of our gravitational-wave statistics. Additionally we show that the first interstellar medium event in PSR J1713+0747 pollutes the common red noise process with low-spectral index noise, and use a tailored noise model to remove these effects., 14 pages, 13 figures, fixed typo in abstract of earlier version

Published
2020

33. The NANOGrav 11 yr Data Set: Limits on Gravitational Wave Memory

Author

A. M. Holgado, K. Islo, Timothy Dolch, Glenn Jones, Nihan Pol, Paul R. Brook, Renée Spiewak, R. van Haasteren, Stephen Taylor, Ryan S. Lynch, Scott M. Ransom, Megan E. DeCesar, Caitlin A. Witt, J. Luo, Adam Brazier, Emmanuel Fonseca, Sean T. McWilliams, Cherry Ng, Peter A. Gentile, Elizabeth C. Ferrara, Chiara M. F. Mingarelli, David J. Nice, Timothy T. Pennucci, Xavier Siemens, Ross J. Jennings, Robert D. Ferdman, David L. Kaplan, Paul Demorest, Duncan R. Lorimer, Fronefield Crawford, Shami Chatterjee, Kevin Stovall, Kathryn Crowter, Zaven Arzoumanian, Neil J. Cornish, Megan L. Jones, Paul S. Ray, E. A. Huerta, N. Garver-Daniels, Joseph Simon, Jeffrey S. Hazboun, Daniel R. Stinebring, Lina Levin, P. T. Baker, Joey Shapiro Key, Sarah Burke-Spolaor, Maura McLaughlin, Michele Vallisneri, James M. Cordes, Michael T. Lam, Wenbai Zhu, Deborah C. Good, Joseph K. Swiggum, H. T. Cromartie, Sarah J. Vigeland, D. R. Madison, Kshitij Aggarwal, J. A. Ellis, Ingrid H. Stairs, Luke Zoltan Kelley, and T. J. W. Lazio

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, 010504 meteorology & atmospheric sciences, Gravitational wave, media_common.quotation_subject, FOS: Physical sciences, Astronomy and Astrophysics, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, 01 natural sciences, General Relativity and Quantum Cosmology, Gravitation, Amplitude, Pulsar, 13. Climate action, Space and Planetary Science, Millisecond pulsar, Observatory, Sky, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common
Abstract

The mergers of supermassive black hole binaries (SMBHBs) promise to be incredible sources of gravitational waves (GWs). While the oscillatory part of the merger gravitational waveform will be outside the frequency sensitivity range of pulsar timing arrays (PTAs), the non-oscillatory GW memory effect is detectable. Further, any burst of gravitational waves will produce GW memory, making memory a useful probe of unmodeled exotic sources and new physics. We searched the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 11-year data set for GW memory. This dataset is sensitive to very low frequency GWs of $\sim3$ to $400$ nHz (periods of $\sim11$ yr $-$ $1$ mon). Finding no evidence for GWs, we placed limits on the strain amplitude of GW memory events during the observation period. We then used the strain upper limits to place limits on the rate of GW memory causing events. At a strain of $2.5\times10^{-14}$, corresponding to the median upper limit as a function of source sky position, we set a limit on the rate of GW memory events at $, Comment: 10 pages, 6 figures, submitted to ApJ

Published
2020

34. The NANOGrav 12.5-year Data Set: Wideband Timing of 47 Millisecond Pulsars

Author

Cherry Ng, Yhamil Garcia, Xavier Siemens, Jing Luo, Robert D. Ferdman, Timothy Dolch, Jordan A. Gusdorff, Paul Demorest, Joseph Simon, Duncan R. Lorimer, Joshua Ramette, Luke Zoltan Kelley, Keeisi Caballero, Emmanuel Fonseca, Justin A. Ellis, Megan E. Decesar, Fronefield Crawford, Scott M. Ransom, David J. Nice, Maura McLaughlin, Shami Chatterjee, Ryan S. Lynch, Megan L. Jones, Kevin Stovall, Cody Jessup, Paul S. Ray, Jeffrey S. Hazboun, D. R. Madison, Joey Shapiro Key, Daniel Halmrast, Chiara M. F. Mingarelli, Daniel R. Stinebring, Caitlin A. Witt, Andrew R. Kaiser, Timothy T. Pennucci, Peter A. Gentile, Renée Spiewak, Faisal Alam, Michael T. Lam, Rachel L. Chamberlain, Michael Tripepi, Paul T. Baker, Harsha Blumer, David L. Kaplan, Ross J. Jennings, Benjamin M. X. Nguyen, Deborah C. Good, Stephen Taylor, Zaven Arzoumanian, James M. Cordes, Richard Camuccio, Neil J. Cornish, Keith E. Bohler, Sarah Burke-Spolaor, K. Islo, Paul R. Brook, Elizabeth C. Ferrara, H. Thankful Cromartie, Brent J. Shapiro-Albert, Michele Vallisneri, Nihan Pol, William Fiore, Weiwei Zhu, Joseph K. Swiggum, T. Joseph W. Lazio, Kaleb Maraccini, Adam Brazier, Nathan Garver-Daniels, Sarah J. Vigeland, and Ingrid H. Stairs

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Gravitational wave, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Data set, Pulsar timing array, Narrowband, Pulsar, Space and Planetary Science, Observatory, Millisecond pulsar, 0103 physical sciences, Wideband, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

We present a new analysis of the profile data from the 47 millisecond pulsars comprising the 12.5-year data set of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), which is presented in a parallel paper (Alam et al. 2021a; NG12.5). Our reprocessing is performed using "wideband" timing methods, which use frequency-dependent template profiles, simultaneous time-of-arrival (TOA) and dispersion measure (DM) measurements from broadband observations, and novel analysis techniques. In particular, the wideband DM measurements are used to constrain the DM portion of the timing model. We compare the ensemble timing results to NG12.5 by examining the timing residuals, timing models, and noise model components. There is a remarkable level of agreement across all metrics considered. Our best-timed pulsars produce encouragingly similar results to those from NG12.5. In certain cases, such as high-DM pulsars with profile broadening, or sources that are weak and scintillating, wideband timing techniques prove to be beneficial, leading to more precise timing model parameters by 10-15%. The high-precision, multi-band measurements of several pulsars indicate frequency-dependent DMs. Compared to the narrowband analysis in NG12.5, the TOA volume is reduced by a factor of 33, which may ultimately facilitate computational speed-ups for complex pulsar timing array analyses. This first wideband pulsar timing data set is a stepping stone, and its consistent results with NG12.5 assure us that such data sets are appropriate for gravitational wave analyses., Comment: 62 pages, 55 figures, 5 tables, 3 appendices. Data available at http://nanograv.org/data/ and via DOI 10.5281/zenodo.4312887

Published
2020
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35. The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

Author

Benjamin M. X. Nguyen, Yhamil Garcia, Jordan A. Gusdorff, Paul R. Brook, Chiara M. F. Mingarelli, Rachel L. Chamberlain, Paul Demorest, Scott M. Ransom, Fronefield Crawford, Timothy Dolch, Stephen Taylor, Luke Zoltan Kelley, Sarah Burke-Spolaor, Joshua Ramette, Shami Chatterjee, Kevin Stovall, Elizabeth C. Ferrara, Robert D. Ferdman, Nathan Garver-Daniels, William Fiore, Peter A. Gentile, T. Joseph W. Lazio, Harsha Blumer, Cody Jessup, Kaleb Maraccini, Caitlin A. Witt, Joseph K. Swiggum, David L. Kaplan, Daniel Halmrast, Paul S. Ray, H. Thankful Cromartie, Brent J. Shapiro-Albert, James M. Cordes, D. R. Madison, Cherry Ng, Daniel R. Stinebring, Sarah J. Vigeland, Joseph Simon, Renée Spiewak, Deborah C. Good, Xavier Siemens, Faisal Alam, Keith E. Bohler, Michael T. Lam, Ryan S. Lynch, Ingrid H. Stairs, Megan E. Decesar, Justin A. Ellis, Emmanuel Fonseca, Maura McLaughlin, Keeisi Caballero, Weiwei Zhu, Joey Shapiro Key, David J. Nice, Timothy T. Pennucci, Duncan R. Lorimer, Paul T. Baker, Richard Camuccio, Neil J. Cornish, Ross J. Jennings, Jing Luo, Andrew R. Kaiser, Megan L. Jones, K. Islo, Jeffrey S. Hazboun, Nihan Pol, Michael Tripepi, Adam Brazier, Zaven Arzoumanian, and Michele Vallisneri

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Gravitational wave, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrometry, Astrophysics, 01 natural sciences, Shapiro delay, Binary pulsar, Pulsar, Space and Planetary Science, Millisecond pulsar, 0103 physical sciences, Arecibo Observatory, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Radio astronomy
Abstract

We present time-of-arrival (TOA) measurements and timing models of 47 millisecond pulsars (MSPs) observed from 2004 to 2017 at the Arecibo Observatory and the Green Bank Telescope by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). The observing cadence was three to four weeks for most pulsars over most of this time span, with weekly observations of six sources. These data were collected for use in low-frequency gravitational wave searches and for other astrophysical purposes. We detail our observational methods and present a set of TOA measurements, based on "narrowband" analysis, in which many TOAs are calculated within narrow radio-frequency bands for data collected simultaneously across a wide bandwidth. A separate set of "wideband" TOAs will be presented in a companion paper. We detail a number of methodological changes compared to our previous work which yield a cleaner and more uniformly processed data set. Our timing models include several new astrometric and binary pulsar measurements, including previously unpublished values for the parallaxes of PSRs J1832-0836 and J2322+2057, the secular derivatives of the projected semi-major orbital axes of PSRs J0613-0200 and J2229+2643, and the first detection of the Shapiro delay in PSR J2145-0750. We report detectable levels of red noise in the time series for 14 pulsars. As a check on timing model reliability, we investigate the stability of astrometric parameters across data sets of different lengths. We report flux density measurements for all pulsars observed. Searches for stochastic and continuous gravitational waves using these data will be subjects of forthcoming publications., Comment: 54 pages, 52 figures, 7 tables, 1 appendix. Data are available at http://nanograv.org/data/ and via the DOI 10.5281/zenodo.4312297

Published
2020
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38. Reduced-Order Modeling with Artificial Neurons for Gravitational-Wave Inference

Author

Chad R. Galley, A. J. K. Chua, and Michele Vallisneri

Subjects
FOS: Computer and information sciences, Basis (linear algebra), Artificial neural network, Computer science, business.industry, Estimation theory, Deep learning, FOS: Physical sciences, General Physics and Astronomy, Inference, Machine Learning (stat.ML), General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, General Relativity and Quantum Cosmology, Statistics - Machine Learning, 0103 physical sciences, Statistical inference, Waveform, Artificial intelligence, Astrophysics - Instrumentation and Methods for Astrophysics, 010306 general physics, business, Instrumentation and Methods for Astrophysics (astro-ph.IM), Algorithm, Interpolation
Abstract

Gravitational-wave data analysis is rapidly absorbing techniques from deep learning, with a focus on convolutional networks and related methods that treat noisy time series as images. We pursue an alternative approach, in which waveforms are first represented as weighted sums over reduced bases (reduced-order modeling); we then train artificial neural networks to map gravitational-wave source parameters into basis coefficients. Statistical inference proceeds directly in coefficient space, where it is theoretically straightforward and computationally efficient. The neural networks also provide analytic waveform derivatives, which are useful for gradient-based sampling schemes. We demonstrate fast and accurate coefficient interpolation for the case of a four-dimensional binary-inspiral waveform family, and discuss promising applications of our framework in parameter estimation., Published version

Published
2019
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39. The International Pulsar Timing Array: Second data release

Author

Sarah Burke-Spolaor, Robert D. Ferdman, Stephen Taylor, Lei Zhang, Janna Goldstein, Caterina Tiburzi, Alberto Sesana, Ingrid H. Stairs, Elizabeth C. Ferrara, N. D. R. Bhat, Benetge Perera, Aditya Parthasarathy, Michael Kramer, H. Hu, Richard N. Manchester, Joseph Simon, L. Lentati, Matthew Kerr, Shi Dai, R. N. Caballero, Megan E. DeCesar, Paul Demorest, A. Possenti, Xing-Jiang Zhu, Kathryn Crowter, Weiwei Zhu, C. G. Bassa, Emmanuel Fonseca, Kejia Lee, Scott M. Ransom, Michael Keith, Stefan Oslowski, Chiara M. F. Mingarelli, D. J. Champion, Ramesh Karuppusamy, David J. Nice, Andrew Lyne, Timothy T. Pennucci, Timothy Dolch, J. K. Swiggum, Benjamin Stappers, K. Islo, Lucas Guillemot, Michele Vallisneri, J. B. Wang, X. Siemens, Gregory Desvignes, Gilles Theureau, James M. Cordes, Ismaël Cognard, Renée Spiewak, Siyuan Chen, Jing Luo, S. A. Sanidas, P. T. Baker, A. Brazier, Songbo Zhang, Alberto Vecchio, George Hobbs, Delphine Perrodin, Michael T. Lam, Jeffrey S. Hazboun, M. Burgay, Daniel J. Reardon, Zaven Arzoumanian, G. Shaifullah, J. W. McKee, Maura McLaughlin, Christopher J. Russell, Sourav Chatterjee, Kang Liu, Matthew Bailes, Gemma H. Janssen, Ryan Shannon, E. Graikou, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Perera, B, Decesar, M, Demorest, P, Kerr, M, Lentati, L, Nice, D, Osłowski, S, Ransom, S, Keith, M, Arzoumanian, Z, Bailes, M, Baker, P, Bassa, C, Bhat, N, Brazier, A, Burgay, M, Burke-Spolaor, S, Caballero, R, Champion, D, Chatterjee, S, Chen, S, Cognard, I, Cordes, J, Crowter, K, Dai, S, Desvignes, G, Dolch, T, Ferdman, R, Ferrara, E, Fonseca, E, Goldstein, J, Graikou, E, Guillemot, L, Hazboun, J, Hobbs, G, Hu, H, Islo, K, Janssen, G, Karuppusamy, R, Kramer, M, Lam, M, Lee, K, Liu, K, Luo, J, Lyne, A, Manchester, R, Mckee, J, Mclaughlin, M, Mingarelli, C, Parthasarathy, A, Pennucci, T, Perrodin, D, Possenti, A, Reardon, D, Russell, C, Sanidas, S, Sesana, A, Shaifullah, G, Shannon, R, Siemens, X, Simon, J, Spiewak, R, Stairs, I, Stappers, B, Swiggum, J, Taylor, S, Theureau, G, Tiburzi, C, Vallisneri, M, Vecchio, A, Wang, J, Zhang, S, Zhang, L, Zhu, W, Zhu, X, Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Technologie de Belfort-Montbeliard (UTBM), PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Ephemeris, 01 natural sciences, Pulsar timing array, stars: neutron, neutron [stars], Pulsar, Millisecond pulsar, Observatory, pulsars: general, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Gravitational wave, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, methods: data analysis, European Pulsar Timing Array, gravitational waves, Space and Planetary Science, [SDU]Sciences of the Universe [physics], pulsars, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Noise (radio), Methods: data analysi
Abstract

In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsar Timing Array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes Pulsar Timing Array. We analyse and where possible combine high-precision timing data for 65 millisecond pulsars which are regularly observed by these groups. A basic noise analysis, including the processes which are both correlated and uncorrelated in time, provides noise models and timing ephemerides for the pulsars. We find that the timing precisions of pulsars are generally improved compared to the previous data release, mainly due to the addition of new data in the combination. The main purpose of this work is to create the most up-to-date IPTA data release. These data are publicly available for searches for low-frequency gravitational waves and other pulsar science., Comment: Submitted to MNRAS and in review, 23 pages, 5 figures

Published
2019
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40. Learning Bayesian posteriors with neural networks for gravitational-wave inference

Author

A. J. K. Chua and Michele Vallisneri

Subjects
FOS: Computer and information sciences, Artificial neural network, Estimation theory, Computer science, Noise (signal processing), Bayesian probability, Detector, General Physics and Astronomy, Inference, FOS: Physical sciences, Machine Learning (stat.ML), General Relativity and Quantum Cosmology (gr-qc), Bayesian inference, 01 natural sciences, General Relativity and Quantum Cosmology, Sampling distribution, Statistics - Machine Learning, 0103 physical sciences, 010306 general physics, Astrophysics - Instrumentation and Methods for Astrophysics, Algorithm, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

We seek to achieve the Holy Grail of Bayesian inference for gravitational-wave astronomy: using deep-learning techniques to instantly produce the posterior $p(\theta|D)$ for the source parameters $\theta$, given the detector data $D$. To do so, we train a deep neural network to take as input a signal + noise data set (drawn from the astrophysical source-parameter prior and the sampling distribution of detector noise), and to output a parametrized approximation of the corresponding posterior. We rely on a compact representation of the data based on reduced-order modeling, which we generate efficiently using a separate neural-network waveform interpolant [A. J. K. Chua, C. R. Galley & M. Vallisneri, Phys. Rev. Lett. 122, 211101 (2019)]. Our scheme has broad relevance to gravitational-wave applications such as low-latency parameter estimation and characterizing the science returns of future experiments. Source code and trained networks are available online at https://github.com/vallis/truebayes., Comment: (Superior-to-)published version; source code and trained networks available at https://github.com/vallis/truebayes

Published
2019
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41. From spin noise to systematics: stochastic processes in the first International Pulsar Timing Array data release

Author

R. van Haasteren, Scott M. Ransom, S. Babak, Antoine Petiteau, Paul Demorest, L. Toomey, Gemma H. Janssen, Alberto Sesana, Marjorie Gonzalez, Sourav Chatterjee, A. Lassus, Ryan Shannon, Justin A. Ellis, Glenn Jones, E. Graikou, J. W. McKee, Kang Liu, Kejia Lee, Matthew Kerr, Sarah Burke-Spolaor, William A. Coles, Maura McLaughlin, G. Shaifullah, Stephen Taylor, Weiwei Zhu, P. Lazarus, S. A. Sanidas, D. J. Champion, Delphine Perrodin, R. N. Caballero, Kevin Stovall, Joris P. W. Verbiest, Benetge Perera, Richard N. Manchester, C. G. Bassa, Emmanuel Fonseca, Jonathan R. Gair, George Hobbs, D. R. Madison, R. Smits, Alberto Vecchio, Daniel R. Stinebring, Michael T. Lam, Daniel J. Reardon, X. P. You, Zaven Arzoumanian, Paul D. Lasky, Yue-Fei Wang, Lucas Guillemot, R. S. Lynch, Pablo Rosado, Lina Levin, Xing-Jiang Zhu, Chiara M. F. Mingarelli, L. Lentati, Benjamin Stappers, A. Possenti, T. J. W. Lazio, Robert D. Ferdman, Stefan Oslowski, J. K. Swiggum, X. Siemens, Gregory Desvignes, Gilles Theureau, Ramesh Karuppusamy, Ismaël Cognard, M. Burgay, Timothy T. Pennucci, Michele Vallisneri, J. B. Wang, James M. Cordes, Sean T. McWilliams, David J. Nice, P. Brem, W. van Straten, Caterina Tiburzi, N. D. R. Bhat, Shi Dai, Jason W. T. Hessels, Ingrid H. Stairs, Timothy Dolch, Michael Kramer, Michael Keith, Lentati, L, Shannon, R, Coles, W, Verbiest, J, van Haasteren, R, Ellis, J, Caballero, R, Manchester, R, Arzoumanian, Z, Babak, S, Bassa, C, Bhat, N, Brem, P, Burgay, M, Burke-Spolaor, S, Champion, D, Chatterjee, S, Cognard, I, Cordes, J, Dai, S, Demorest, P, Desvignes, G, Dolch, T, Ferdman, R, Fonseca, E, Gair, J, Gonzalez, M, Graikou, E, Guillemot, L, Hessels, J, Hobbs, G, Janssen, G, Jones, G, Karuppusamy, R, Keith, M, Kerr, M, Kramer, M, Lam, M, Lasky, P, Lassus, A, Lazarus, P, Lazio, T, Lee, K, Levin, L, Liu, K, Lynch, R, Madison, D, Mckee, J, Mclaughlin, M, Mcwilliams, S, Mingarelli, C, Nice, D, Osłowski, S, Pennucci, T, Perera, B, Perrodin, D, Petiteau, A, Possenti, A, Ransom, S, Reardon, D, Rosado, P, Sanidas, S, Sesana, A, Shaifullah, G, Siemens, X, Smits, R, Stairs, I, Stappers, B, Stinebring, D, Stovall, K, Swiggum, J, Taylor, S, Theureau, G, Tiburzi, C, Toomey, L, Vallisneri, M, van Straten, W, Vecchio, A, Wang, J, Wang, Y, You, X, Zhu, W, Zhu, X, High Energy Astrophys. & Astropart. Phys (API, FNWI), Cavendish Laboratory, University of Cambridge [UK] (CAM), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), University of California, University of California (UC), Max-Planck-Institut für Radioastronomie (MPIFR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), Max-Planck-Gesellschaft, Netherlands Institute for Radio Astronomy (ASTRON), Curtin University [Perth], Planning and Transport Research Centre (PATREC), INAF - Osservatorio Astronomico di Cagliari (OAC), Istituto Nazionale di Astrofisica (INAF), National Radio Astronomy Observatory (NRAO), Center for Radiophysics and Space Research [Ithaca] (CRSR), Cornell University [New York], Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Department of Astronomy [Ithaca], Department of Physics, Hillsdale College, Unité Scientifique de la Station de Nançay (USN), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), University of British Columbia (UBC), Vancouver Coastal Health, Department of Nuclear Medicine, Netherlands Institute for Radio Astronomy ( ASTRON ), ARC Centre of Excellence for Coral Reef Studies (CoralCoE), James Cook University (JCU), Jodrell Bank Centre for Astrophysics, University of Manchester [Manchester], Vrije Universiteit Medical Centre (VUMC), Vrije Universiteit Amsterdam [Amsterdam] (VU), Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], National Radio Astronomy Observatory [Green Bank] (NRAO), Jodrell Bank Centre for Astrophysics (JBCA), Department of Physics, West Virginia University, West Virginia University, Theoretical Astrophysics [Pasadena] (TAPIR), California Institute of Technology (CALTECH), Physics Department, Lafayette College, Lafayette College [Easton], Department of Astronomy [Charlottesville], University of Virginia, APC - Gravitation (APC-Gravitation), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre for Astrophysics and Supercomputing [Swinburne] (CAS), Swinburne University of Technology [Melbourne], Anton Pannekoek Institute for Astronomy, University of Amsterdam [Amsterdam] (UvA), University of Wisconsin - Milwaukee, Department of Physics and Astronomy, University of British Columbia, Department of Physics and Astronomy [Oberlin], Oberlin College, Institute of Meteoritics [Albuquerque] (IOM), The University of New Mexico [Albuquerque], Department of Physics and Astronomy, West Virginia University, West Virginia University [Morgantown], Birmingham City University (BCU), Xinjiang Astronomical Observatory, Chinese Academy of Sciences [Beijing] (CAS), Huazhong University of Science and Technology [Wuhan] (HUST), School of Physical Science and Technology, Southwest University [Chongqing], Australian Research Council Discovery Project DP140102578NASA through Einstein Fellowship grant PF3-140116West Light Foundation of CAS XBBS201322 and NSFC project no.11403086National Science Fundation of China (NSFC) award number 11503007NNSF of China (U1231120) and FRFCU (XDJK2015B012), European Project: 337062,EC:FP7:ERC,ERC-2013-StG,DRAGNET(2014), European Project: 227947,EC:FP7:ERC,ERC-2008-AdG,LEAP(2009), European Project: 610058,EC:FP7:ERC,ERC-2013-SyG,BLACKHOLECAM(2014), Cornell University, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Division of Physics, Mathematics and Astronomy [Pasadena], California Institute of Technology (CALTECH)-California Institute of Technology (CALTECH), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), California Institute of Technology (CALTECH)-NASA, Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), University of Virginia [Charlottesville], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, data analysis, pulsars: general [methods], FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Methods: Data analysi, Astrophysics, Astronomy & Astrophysics, general [pulsars], 01 natural sciences, General Relativity and Quantum Cosmology, pulsars:individual, Binary pulsar, Pulsar, 0103 physical sciences, data analysis [methods], Coherence (signal processing), Sensitivity (control systems), Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Stochastic process, Noise (signal processing), Model selection, Pulsars: General, Astronomy and Astrophysics, methods: data analysis, LIGO, Computational physics, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astronomical and Space Sciences
Abstract

We analyse the stochastic properties of the 49 pulsars that comprise the first International Pulsar Timing Array (IPTA) data release. We use Bayesian methodology, performing model selection to determine the optimal description of the stochastic signals present in each pulsar. In addition to spin-noise and dispersion-measure (DM) variations, these models can include timing noise unique to a single observing system, or frequency band. We show the improved radio-frequency coverage and presence of overlapping data from different observing systems in the IPTA data set enables us to separate both system and band-dependent effects with much greater efficacy than in the individual PTA data sets. For example, we show that PSR J1643$-$1224 has, in addition to DM variations, significant band-dependent noise that is coherent between PTAs which we interpret as coming from time-variable scattering or refraction in the ionised interstellar medium. Failing to model these different contributions appropriately can dramatically alter the astrophysical interpretation of the stochastic signals observed in the residuals. In some cases, the spectral exponent of the spin noise signal can vary from 1.6 to 4 depending upon the model, which has direct implications for the long-term sensitivity of the pulsar to a stochastic gravitational-wave (GW) background. By using a more appropriate model, however, we can greatly improve a pulsar's sensitivity to GWs. For example, including system and band-dependent signals in the PSR J0437$-$4715 data set improves the upper limit on a fiducial GW background by $\sim 60\%$ compared to a model that includes DM variations and spin-noise only., Comment: 29 pages. 16 figures. Accepted for publication in MNRAS

Published
2016
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42. The International Pulsar Timing Array: First data release

Author

Lucas Guillemot, Sourav Chatterjee, N. Garver-Daniels, D. R. Madison, Scott M. Ransom, J. K. Swiggum, Daniel R. Stinebring, Delphine Perrodin, Ingrid H. Stairs, Alberto Vecchio, Timothy Dolch, X. Siemens, Gregory Desvignes, Antoine Petiteau, Gilles Theureau, W. van Straten, J. B. Wang, X. P. You, Jason W. T. Hessels, Renée Spiewak, R. N. Caballero, Alberto Sesana, Stefan Oslowski, R. S. Lynch, Xing-Jiang Zhu, C. G. Bassa, Emmanuel Fonseca, Daniel J. Reardon, Yue-Fei Wang, Chiara M. F. Mingarelli, Benjamin Stappers, Kejia Lee, Stanislav Babak, Benetge Perera, Pablo Rosado, Zaven Arzoumanian, Richard N. Manchester, Paul Demorest, A. Brazier, Jonathan R. Gair, R. van Haasteren, Nipuni Palliyaguru, Lina Levin, R. Smits, Joseph Simon, P. Brem, Michele Vallisneri, Michael Kramer, James M. Cordes, Andrew Lyne, L. Lentati, Weiwei Zhu, Matthew Kerr, Peter A. Gentile, Michael Keith, A. Possenti, D. J. Champion, Caterina Tiburzi, T. J. W. Lazio, N. D. R. Bhat, A. Lassus, Stephen Taylor, Linqing Wen, Ryan Shannon, Glenn Jones, Shi Dai, E. Graikou, Gemma H. Janssen, S. J. Chamberlin, Kevin Stovall, Kang Liu, P. Lazarus, Ramesh Karuppusamy, S. A. Sanidas, Ismaël Cognard, George Hobbs, Robert D. Ferdman, Timothy T. Pennucci, M. Burgay, Sean T. McWilliams, David J. Nice, B. Christy, G. Shaifullah, L. Toomey, Justin A. Ellis, J. W. McKee, Maura McLaughlin, Paul D. Lasky, Michael T. Lam, Sarah Burke-Spolaor, Joris P. W. Verbiest, Marjorie Gonzalez, High Energy Astrophys. & Astropart. Phys (API, FNWI), Verbiest, J, Lentati, L, Hobbs, G, van Haasteren, R, Demorest, P, Janssen, G, Wang, J, Desvignes, G, Caballero, R, Keith, M, Champion, D, Arzoumanian, Z, Babak, S, Bassa, C, Bhat, N, Brazier, A, Brem, P, Burgay, M, Burke-Spolaor, S, Chamberlin, S, Chatterjee, S, Christy, B, Cognard, I, Cordes, J, Dai, S, Dolch, T, Ellis, J, Ferdman, R, Fonseca, E, Gair, J, Garver-Daniels, N, Gentile, P, Gonzalez, M, Graikou, E, Guillemot, L, Hessels, J, Jones, G, Karuppusamy, R, Kerr, M, Kramer, M, Lam, M, Lasky, P, Lassus, A, Lazarus, P, Lazio, T, Lee, K, Levin, L, Liu, K, Lynch, R, Lyne, A, Mckee, J, Mclaughlin, M, Mcwilliams, S, Madison, D, Manchester, R, Mingarelli, C, Nice, D, Osłowski, S, Palliyaguru, N, Pennucci, T, Perera, B, Perrodin, D, Possenti, A, Petiteau, A, Ransom, S, Reardon, D, Rosado, P, Sanidas, S, Sesana, A, Shaifullah, G, Shannon, R, Siemens, X, Simon, J, Smits, R, Spiewak, R, Stairs, I, Stappers, B, Stinebring, D, Stovall, K, Swiggum, J, Taylor, S, Theureau, G, Tiburzi, C, Toomey, L, Vallisneri, M, van Straten, W, Vecchio, A, Wang, Y, Wen, L, You, X, Zhu, W, Zhu, X, Max-Planck-Institut für Radioastronomie (MPIFR), Cavendish Laboratory, University of Cambridge [UK] (CAM), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), National Radio Astronomy Observatory [Socorro] (NRAO), National Radio Astronomy Observatory (NRAO), Netherlands Institute for Radio Astronomy (ASTRON), Xinjiang Astronomical Observatory, Chinese Academy of Sciences [Beijing] (CAS), Jodrell Bank Centre for Astrophysics, University of Manchester [Manchester], NASA Goddard Space Flight Center (GSFC), Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), Max-Planck-Gesellschaft, Curtin University [Perth], Planning and Transport Research Centre (PATREC), Cornell Center for Astrophysics and Planetary Science (CCAPS), Cornell University [New York], INAF - Osservatorio Astronomico di Cagliari (OAC), Istituto Nazionale di Astrofisica (INAF), Pennsylvania State University (Penn State), Penn State System, Center for Radiophysics and Space Research [Ithaca] (CRSR), University of Maryland [College Park], University of Maryland System, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO), Department of Astronomy [Ithaca], Department of Physics, Hillsdale College, University of British Columbia (UBC), University of Edinburgh, Department of Physics and Astronomy, West Virginia University, West Virginia University [Morgantown], Vancouver Coastal Health, Department of Nuclear Medicine, Department of Physics, Columbia University, Columbia University [New York], Monash Centre for Astrophysics (MoCA), Monash University [Clayton], Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], National Radio Astronomy Observatory [Green Bank] (NRAO), Theoretical Astrophysics [Pasadena] (TAPIR), Division of Physics, Mathematics and Astronomy [Pasadena], California Institute of Technology (CALTECH)-California Institute of Technology (CALTECH), Physics Department, Lafayette College, Lafayette College [Easton], Physics Department, Texas Tech University, Texas Tech University [Lubbock] (TTU), Department of Astronomy [Charlottesville], University of Virginia [Charlottesville], APC - Gravitation (APC-Gravitation), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Centre for Astrophysics and Supercomputing [Swinburne] (CAS), Swinburne University of Technology [Melbourne], Anton Pannekoek Institute for Astronomy, University of Amsterdam [Amsterdam] (UvA), University of Wisconsin - Milwaukee, Center for Gravitation, Cosmology and Astrophysics, Netherlands Institute for Radio Astronomy ( ASTRON ), Department of Physics and Astronomy, University of British Columbia, Department of Physics and Astronomy [Oberlin], Oberlin College, Department of Physics and Astronomy [Albuquerque], The University of New Mexico [Albuquerque], Birmingham City University (BCU), School of Physics [HUST], Huazhong University of Science and Technology [Wuhan] (HUST), School of Physics (University of Western Australia), Université, School of Physical Science and Technology, Southwest University [Chongqing], European Project: 337062,EC:FP7:ERC,ERC-2013-StG,DRAGNET(2014), Max-Planck-Institut für Radioastronomie, Cavendish Laboratory - University of Cambridge, University of Cambridge [UK] ( CAM ), CSIRO Astronomy and Space Science, PO BOX 76, NSW 1710, Australia, Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), National Radio Astronomy Observatory [Socorro] ( NRAO ), National Radio Astronomy Observatory ( NRAO ), Netherlands Institute for Radio Astronomy, Chinese Academy of Sciences [Beijing] ( CAS ), NASA Goddard Space Flight Center ( GSFC ), Albert Einstein Institute, Max-Planck-Institut für Gravitationsphysik, Curtin University, Perth, Australia, Cornell Center for Astrophysics and Planetary Science ( CCAPS ), Cornell University, MPI for Gravitational Physics (Albert Einstein Institute), INAF-Osservatorio di Cagliari, PennState University [Pennsylvania] ( PSU ), Center for Radiophysics and Space Research [Ithaca] ( CRSR ), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace ( LPC2E ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Unité Scientifique de la Station de Nançay ( USN ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), University of British Columbia ( UBC ), University of Edimburgh, Kavli Institute for Astronomy and Astrophysics, National Radio Astronomy Observatory [Green Bank] ( NRAO ), Commonwealth Scientific and Industrial Research Organisation [Canberra] ( CSIRO ), TAPIR (Theoretical Astrophysics), California Institute of Technology, Texas Tech University [Lubbock] ( TTU ), Osservatorio Astronomico di Cagliari, Ist Nazl Astrofis, Osservatorio Astronomico di Cagliari, APC - Gravitation ( APC-Gravitation ), AstroParticule et Cosmologie ( APC - UMR 7164 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Max-Planck-Institut-Max-Planck-Institut, Centre for Astrophysics and Supercomputing [Swinburne] ( CAS ), Anton Pannekoek Institute for Astronomy, University of Amsterdam, Max Planck Institut für Gravitationsphysik, Albert Einstein Institut, Physics and Astronomy Department [Oberlin], Center for Gravitational Wave Astronomy, The University of Texas at Brownsville and Texas Southmost College, Birmingham City University ( BCU ), School of Physics, Huazhong University of Science and Technology, Huazhong University of Science and Technology, School of Physics ( University of Western Australia ), European Project : 337062,EC:FP7:ERC,ERC-2013-StG,DRAGNET ( 2014 ), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), University of Virginia, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI)

Subjects
data analysis, data analysis, pulsars: general [methods], FOS: Physical sciences, Methods: Data analysi, general [pulsars], 01 natural sciences, 7. Clean energy, Set (abstract data type), Pulsar timing array, Pulsar, 0103 physical sciences, data analysis [methods], Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, instrumentation, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Gravitational wave, Astrophysics::Instrumentation and Methods for Astrophysics, Pulsars: General, Astronomy, Astronomy and Astrophysics, methods: data analysis, Data set, European Pulsar Timing Array, Neutron star, gravitational waves, Space and Planetary Science, pulsars, Measurement uncertainty, Astrophysics - Instrumentation and Methods for Astrophysics, [ SDU.ASTR.SR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Algorithm, astro-ph.IM
Abstract

The highly stable spin of neutron stars can be exploited for a variety of (astro-)physical investigations. In particular arrays of pulsars with rotational periods of the order of milliseconds can be used to detect correlated signals such as those caused by gravitational waves. Three such "Pulsar Timing Arrays" (PTAs) have been set up around the world over the past decades and collectively form the "International" PTA (IPTA). In this paper, we describe the first joint analysis of the data from the three regional PTAs, i.e. of the first IPTA data set. We describe the available PTA data, the approach presently followed for its combination and suggest improvements for future PTA research. Particular attention is paid to subtle details (such as underestimation of measurement uncertainty and long-period noise) that have often been ignored but which become important in this unprecedentedly large and inhomogeneous data set. We identify and describe in detail several factors that complicate IPTA research and provide recommendations for future pulsar timing efforts. The first IPTA data release presented here (and available online) is used to demonstrate the IPTA's potential of improving upon gravitational-wave limits placed by individual PTAs by a factor of ~2 and provides a 2-sigma limit on the dimensionless amplitude of a stochastic GWB of 1.7x10^{-15} at a frequency of 1 yr^{-1}. This is 1.7 times less constraining than the limit placed by (Shannon et al. 2015), due mostly to the more recent, high-quality data they used., 25 pages, 6 tables, 5 figures. Accepted for publication in MNRAS

Published
2016
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43. The NANOGrav 12.5 yr Data Set: Search for an Isotropic Stochastic Gravitational-wave Background

Author

Harsha Blumer, D. R. Madison, Ryan S. Lynch, Paul Demorest, Deborah C. Good, Paul R. Brook, Megan L. Jones, Renée Spiewak, Paul T. Baker, Nathan Garver-Daniels, Jeffrey S. Hazboun, Luke Zoltan Kelley, A. Miguel Holgado, Scott M. Ransom, Caitlin A. Witt, Neil J. Cornish, Nima Laal, Joseph Simon, Timothy T. Pennucci, Michele Vallisneri, Jing Luo, Siyuan Chen, Fronefield Crawford, Zaven Arzoumanian, Ross J. Jennings, Chiara M. F. Mingarelli, Joey Shapiro Key, Elizabeth C. Ferrara, Shami Chatterjee, Cherry Ng, Adam Brazier, Jerry P. Sun, Kevin Stovall, Sarah Burke-Spolaor, Sarah J. Vigeland, Xavier Siemens, James M. Cordes, William Fiore, Timothy Dolch, Joseph K. Swiggum, Peter A. Gentile, H. Thankful Cromartie, Brent J. Shapiro-Albert, Jacob E. Turner, Paul S. Ray, B. Bécsy, David J. Nice, David L. Kaplan, T. Joseph W. Lazio, Ingrid H. Stairs, K. Islo, Nihan Pol, Duncan R. Lorimer, Justin A. Ellis, Maura McLaughlin, Andrew R. Kaiser, Michael T. Lam, Megan E. DeCesar, Emmanuel Fonseca, Stephen Taylor, Daniel R. Stinebring, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), NANOGrav, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES)

Subjects
noise, gravitational radiation: stochastic, 010504 meteorology & atmospheric sciences, General relativity, Population, Astrophysics, Bayesian, 01 natural sciences, General Relativity and Quantum Cosmology, Gravitational wave background, Pulsar, Millisecond pulsar, 0103 physical sciences, general relativity, black hole, education, 010303 astronomy & astrophysics, pulsar, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, education.field_of_study, Gravitational wave, gravitational radiation: background, Astronomy and Astrophysics, solar system, Astrophysics - Astrophysics of Galaxies, observatory, Black hole, Amplitude, black hole: binary, [SDU]Sciences of the Universe [physics], Space and Planetary Science, correlation, slope, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], spectral, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We search for an isotropic stochastic gravitational-wave background (GWB) in the $12.5$-year pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. Our analysis finds strong evidence of a stochastic process, modeled as a power-law, with common amplitude and spectral slope across pulsars. The Bayesian posterior of the amplitude for an $f^{-2/3}$ power-law spectrum, expressed as the characteristic GW strain, has median $1.92 \times 10^{-15}$ and $5\%$--$95\%$ quantiles of $1.37$--$2.67 \times 10^{-15}$ at a reference frequency of $f_\mathrm{yr} = 1 ~\mathrm{yr}^{-1}$. The Bayes factor in favor of the common-spectrum process versus independent red-noise processes in each pulsar exceeds $10,000$. However, we find no statistically significant evidence that this process has quadrupolar spatial correlations, which we would consider necessary to claim a GWB detection consistent with general relativity. We find that the process has neither monopolar nor dipolar correlations, which may arise from, for example, reference clock or solar system ephemeris systematics, respectively. The amplitude posterior has significant support above previously reported upper limits; we explain this in terms of the Bayesian priors assumed for intrinsic pulsar red noise. We examine potential implications for the supermassive black hole binary population under the hypothesis that the signal is indeed astrophysical in nature., Comment: 25 pages, 14 figures, 5 tables, 3 appendices. Published in The Astrophysical Journal Letters. Please send any comments/questions to Joseph Simon (joe.simon@nanograv.org). Jupyter notebook tutorials and some MCMC chain files are available at https://github.com/nanograv/12p5yr_stochastic_analysis

Published
2020
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44. The NANOGrav 11 Year Data Set:Pulsar-timing Constraints on the Stochastic Gravitational-wave Background

Author

Megan E. DeCesar, Renée Spiewak, Timothy Dolch, Timothy T. Pennucci, Emmanuel Fonseca, Alexander Rasskazov, D. R. Madison, Elizabeth C. Ferrara, Jing Luo, Justin A. Ellis, David L. Kaplan, William M. Folkner, V. M. Kaspi, B. Christy, Maura McLaughlin, T. J. W. Lazio, Neil J. Cornish, Weiwei Zhu, Ryan S. Park, P. T. Baker, Sean T. McWilliams, Joseph Simon, Glenn Jones, Stephen Taylor, Ryan S. Lynch, David J. Nice, Jeffrey S. Hazboun, Kathryn Crowter, Michael T. Lam, Paul S. Ray, E. A. Huerta, Peter A. Gentile, K. Islo, Daniel R. Stinebring, Nihan Pol, M. L. Jones, Chiara M. F. Mingarelli, Sarah Burke-Spolaor, Andrea N. Lommen, Roland Haas, Sarah J. Vigeland, Lina Levin, Robert D. Ferdman, S. J. Chamberlin, Fronefield Crawford, Joseph K. Swiggum, Shami Chatterjee, Kevin Stovall, Ingrid H. Stairs, H. Thankful Cromartie, Michele Vallisneri, James M. Cordes, Scott M. Ransom, R. van Haasteren, Adam Brazier, Cherry Ng, Xavier Siemens, Paul Demorest, Zaven Arzoumanian, N. Garver-Daniels, and Duncan R. Lorimer

Subjects
Stellar mass, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics, General Relativity and Quantum Cosmology (gr-qc), Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, general [pulsars], General Relativity and Quantum Cosmology, Gravitational wave background, Pulsar timing array, Pulsar, 0103 physical sciences, data analysis [methods], ephemeredes, inflation, education, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, Supermassive black hole, 010308 nuclear & particles physics, Gravitational wave, supermassive black holes [quasars], Astronomy and Astrophysics, Quasar, 16. Peace & justice, Astrophysics - Astrophysics of Galaxies, gravitational waves, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena
Abstract

We search for an isotropic stochastic gravitational-wave background (GWB) in the newly released $11$-year dataset from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). While we find no significant evidence for a GWB, we place constraints on a GWB from a population of supermassive black-hole binaries, cosmic strings, and a primordial GWB. For the first time, we find that the GWB upper limits and detection statistics are sensitive to the Solar System ephemeris (SSE) model used, and that SSE errors can mimic a GWB signal. We developed an approach that bridges systematic SSE differences, producing the first PTA constraints that are robust against SSE uncertainties. We thus place a $95\%$ upper limit on the GW strain amplitude of $A_\mathrm{GWB}, 21 pages, 12 figures, 9 tables. Published in The Astrophysical Journal. Please send any comments/questions to S. R. Taylor (srtaylor@caltech.edu)

Published
2018
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45. A Gaussian Mixture Model for Nulling Pulsars

Author

David L. Kaplan, Joseph K. Swiggum, Travis D. J. Fichtenbauer, and Michele Vallisneri

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Improved algorithm, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Mixture model, 01 natural sciences, Measure (mathematics), Methods statistical, 010104 statistics & probability, Pulsar, Turn off, Space and Planetary Science, Simulated data, 0103 physical sciences, Line (geometry), 0101 mathematics, Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Algorithm, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The phenomenon of pulsar nulling -- where pulsars occasionally turn off for one or more pulses -- provides insight into pulsar-emission mechanisms and the processes by which pulsars turn off when they cross the "death line." However, while ever more pulsars are found that exhibit nulling behavior, the statistical techniques used to measure nulling are biased, with limited utility and precision. In this paper we introduce an improved algorithm, based on Gaussian mixture models, for measuring pulsar nulling behavior. We demonstrate this algorithm on a number of pulsars observed as part of a larger sample of nulling pulsars, and show that it performs considerably better than existing techniques, yielding better precision and no bias. We further validate our algorithm on simulated data. Our algorithm is widely applicable to a large number of pulsars even if they do not show obvious nulls. Moreover, it can be used to derive nulling probabilities of nulling for individual pulses, which can be used for in-depth studies., Comment: 7 pages, 7 figures. Accepted for publication by AAS journals

Published
2018

46. First Search for Nontensorial Gravitational Waves from Known Pulsars

Author

F. Frasconi, R. Flaminio, J.-P. Coulon, S. T. Countryman, Andrew Matas, R. Kirchhoff, B. L. Pearlstone, D. M. Macleod, J. Moore, B. L. Swinkels, J. M. Gonzalez Castro, G. Bergmann, D. Passuello, J. Daw, B. D. Cheeseboro, G. Cerretani, A. Cirone, C. Ferreira, V. Tiwari, Yann Bouffanais, T. Huynh-Dinh, S. R. Morriss, D. Barta, H. Cao, D. J. Vine, L. Willis, J. Calderón Bustillo, Edward K. Porter, John T. Kissel, Marc Favata, M. Perri, Roger Jones, V. J. Roma, A. P. Spencer, Anthony A. Amato, N. van Bakel, V. Kringel, Jacob Broida, F. Garufi, Lucas Guillemot, C. Messenger, D. Bersanetti, Piotr Jaranowski, Tyson Littenberg, Leopoldo Milano, V. Fafone, A. Masserot, J. Owen, Kendall Ackley, R. K. Nayak, K. Kawabe, S. N. Tiwari, S. M. Aston, K. Ueno, A. Strain, Michael W. Coughlin, P. Singer, Odylio D. Aguiar, Bala R. Iyer, Surabhi Sachdev, Christopher J. Moore, M. Scott, S. McCormick, P. Spencer, V. V. Frolov, M. M. Reid, A. Singhal, A. Bizouard, N. Leroy, J. Camp, P. Coulon, Chunnong Zhao, Badri Krishnan, A. Sonnenberg, D. Fiorucci, A. R. Wade, G. Kuehn, F. Magaña-Sandoval, L. Byer, Benoit Sassolas, V. Kondrashov, Stanislav Babak, Arunava Mukherjee, Y. Minenkov, K. Lanza, H. Wittel, S. G. Schwalbe, M. Phelps, R. G. Ormiston, I. Khan, I. Torrie, T. D. Canton, B. Day, C. Aulbert, W. D. Vousden, L. Matone, Haocun Yu, B. Agarwal, B. Bécsy, M. Kasprzack, C. M. Mow-Lowry, Sergey P. Vyatchanin, E. Schreiber, P. J. Sutton, G. Thomas, J. H. Romie, F. J. Raab, M. H. Wimmer, C. Krämer, C. C. Buchanan, P. Popolizio, Koji Arai, E. J. Sanchez, M. Shoemaker, M. Gosselin, E. E. Cowan, Sarah Williams, S. Gaudio, M. Constancio, S. Karki, T. J. Cullen, R. Douglas, N. Mukund, A. K. W. Chung, S. Mastrogiovanni, R. K. Lanza, Sumit Kumar, B. F. Whiting, P. Abbott, Kin Fai Ellick Wong, J. Casanueva Diaz, P. Schale, V. Germain, S. Gomes, A. Huerta, C. Lazzaro, Patricia Schmidt, A. Avila-Alvarez, V. Brisson, K. S. Karvinen, L. R. Cominsky, R. Gustafson, P. Thomas, John A. Clark, Ben Farr, Christophe Collette, C. J. Perez, N. Gehrels, Marek Szczepanczyk, P. Oppermann, K. Gill, Frédérique Marion, Charalampos Markakis, Michael Pürrer, Walter Winkler, A. S. Markosyan, Harald Lück, M. Boer, L. E. Wade, G. Kang, A. Pal-Singh, R. L. Savage, A. S. Bell, J. L. Willis, M. Laxen, C. Van Den Broeck, Sylvia J. Zhu, D. Verkindt, S. Buchner, P. T.H. Pang, R. Tso, Patrick M. Koch, J. A. Taylor, Michele Vallisneri, P. Berry, Ik Siong Heng, M. Fays, J. Page, P. Astone, Larne Pekowsky, W. K. Wong, Serena Vinciguerra, R. Pedurand, Benno Willke, K. W. Tsang, Samuel Deléglise, A. Fernandez-Galiana, Miftar Ganija, D. Huet, J. King, J. Shaffer, S. H. Huttner, J. D. Jones, G. Wu, S. Raja, S. E. Strigin, Roy Williams, Anthony G. A. Brown, Mairi Sakellariadou, C. Vander-Hyde, G. Pillant, Tenglin Li, M. Guidi, I. Kowalska, Marie-Anne Bizouard, C. Cahillane, J. Hennig, A. Khazanov, V. Gayathri, S. Walsh, Miriam Cabero, A. Muniz, A. Di Lieto, M. Saleem, M. Cho, C. Pankow, J. A. Sonnenberg, A. L. Stuver, P. M. Meyers, Jing Wang, Jiayi Qin, A. Singer, László Á. Gergely, M. Harry, S. Banagiri, A. Pele, M. Rakhmanov, E. Mejuto-Villa, T. Etzel, Patrick Weltevrede, B. D. Lackey, I. Magaña Hernandez, Kipp Cannon, M. Steinke, R. Mittleman, Nelson Christensen, Barry C. Barish, Nergis Mavalvala, Jerome Degallaix, A. Hannuksela, C. Casentini, Sebastian Khan, B. C. Stephens, Paul J. Groot, M. Zevin, B. W. Schulte, F. Y. Khalili, S. J. Chamberlin, M. Vasúth, Howard Pan, Aaron Buikema, C. C. Wipf, E. J. King, C. S. Unnikrishnan, G. Gaur, S. C. McGuire, J. F. Read, S. Di Pace, Tomasz Bulik, Richard J. Oram, M. C. Heintze, Andrew Melatos, M. Lorenzini, M. Thomas, M. J. Yap, Alessandra Buonanno, R. Metzdorff, C.-J. Haster, Gabrielle Allen, J.-M. Isac, J. B. Kanner, H. Fong, G. Greco, François Bondu, J. Zweizig, Samuele Cortese, John Veitch, Vladimir B. Braginsky, J. Oram, J. Lehmann, C. Palomba, H. Vahlbruch, K. Riles, Jonathan Cripe, H. Middleton, C. Beer, J. C. Barayoga, Lloyd Paul Aiello, B. C. Pant, N. Indik, W. W. Johnson, D. Aguiar, A. Giazotto, N. Arnaud, Maggie Tse, M. S. Shahriar, M. Bejger, D. B. Tanner, E. L. Merilh, M. J. Cowart, K. E. Ramirez, P. Downes, M. Afrough, F. Jiménez-Forteza, Sourav Ghosh, Imre Bartos, H. Fehrmann, M. Factourovich, S. Cho, C. R. Billman, F. Cleva, S. G. Crowder, N. Kijbunchoo, K. Wessel, F. Carbognani, Sebastian Steinlechner, Vijay Varma, Soumi De, M. Weinert, H. A. G. Gabbard, M. MacInnis, F. Fidecaro, G. M. Guidi, Sibilla Di Pace, P. Ross, E. A. Houston, P. Shawhan, I. Ferrante, J. McIver, P. Puppo, A. W. Muir, P. Charlton, Kejia Lee, I. Maksimovic, S. Mitra, D. V. Voss, R. L. Ward, Otto A. Hannuksela, Lu Zhang, Rana X. Adhikari, M. Korobko, B. U. Gadre, Sebastien Biscans, G. Hemming, G. McIntyre, T. B. Edo, M. Pichot, Maximiliano Isi, Leo Singer, N. Letendre, P. Drever, Abhirup Ghosh, M. Aston, H. Ogin, H. N. Isa, M. Nery, B. Machenschalk, F. Donovan, S. A. Usman, Roman Schnabel, J. E. Brau, Karsten Danzmann, A. A. van Veggel, Javier Sánchez, Hua Wang, B. Tanner, P. Rapagnani, Andreas Freise, Vincenzo Pierro, Paul D. Lasky, Matthew Pitkin, R. K.L. Lo, E. A. Huerta, M. Granata, Ettore Majorana, R. Goetz, Tarun Souradeep, M. Fries, C. L. Romel, E. Katsavounidis, V. Quetschke, M. Was, S. M. Koehlenbeck, H. Vocca, Eugeniy E. Mikhailov, Bangalore Suryanarayana Sathyaprakash, L. Rolland, Fabrizio Barone, M. Mohan, N. Man, K. Haughian, A. Quintero, Martin M. Fejer, J. R. Smith, R. Bork, S. Ghonge, K. AultONeal, M. Punturo, J. Betzwieser, Q. Chu, Slawomir Gras, John Miller, Matthew Ross, Lionel Martellini, M. E. N. Normandin, H. Shoemaker, S. Areeda, Madeline Wade, P. Leaci, A. Colla, L. Mansell, Y. Khalili, D. Nolting, Ryan Magee, J. W. W. Pratt, Gregory M. Harry, M. Ast, R. Kennedy, Efim A. Khazanov, G. Ballardin, K. Porter, Antoine Heidmann, Geoffrey Lovelace, H. Lai, P. A. Altin, Alvin J. K. Chua, D. Barker, Denis Martynov, Marco Bazzan, K. H. Lai, A. A. Shah, Minchuan Zhou, J. Haster, D. J. McManus, Vuk Mandic, Peter Fritschel, M. Masso-Reid, D. Töyrä, H. Radkins, H. Overmier, A. Bozzi, C. Baune, D. Sellers, Alessandro Ridolfi, M. Hu, C. F. Da Silva Costa, M. Neri, D. Lumaca, J. A. Giaime, J. Meidam, L. Pinard, Aaron Viets, Sung-Po Chao, R. De Rosa, M. C. Tringali, Peter Weßels, Zifan Zhou, I. A. Bilenko, David J. Ottaway, A. Paoli, M. Gaebel, D. Talukder, S. Rabeling, David A. Williams, D. C. Vander-Hyde, I. W. Harry, H. Qi, L. Magaña Zertuche, I. Nardecchia, Carlos Cepeda, M. Branchesi, J. C. Batch, A. Gennai, Rahul Kumar, Harald P. Pfeiffer, M. Farr, K. Mason, J. Mcmanus, J. Devenson, D. Hall, A. Chiummo, H.-B. Eggenstein, Luca Gammaitoni, J. Zhu, P. T. Baker, R. Robie, P. Ehrens, Paul M. Ricker, M. Brinkmann, Anders Nielsen, S. Kaufer, Rainer Weiss, Ashutosh Kumar Singh, F. Ricci, Alessandro Corongiu, Y. M. Kim, Hsiao-Wen Chen, Federico Ferrini, Lijing Shao, G. Vajente, S. M. Gaebel, T. Prestegard, K. K.Y. Ng, Riccardo Sturani, Robert J. McCarthy, Linqing Wen, A. Sheperd, E. C. Ferreira, Sanjeev Dhurandhar, M. Sampson, Ryan Shannon, Z. Tornasi, I. Di Palma, M. Rizzo, V. Predoi, I. W. Martin, David E. McClelland, S. Appert, P. B. Covas, Edward Seidel, F. Clara, Tristan Briant, O. E. S. Sauter, J. Feicht, B. Sandeen, M. C. Edwards, L. Naticchioni, Salvatore Vitale, S. Sathyaprakash, Joey Shapiro Key, Yu Zhang, S. Ascenzi, Kip S. Thorne, J. R. Sanders, Gang Wang, Alessandro Bertolini, J. C. Driggers, R. W. P. Drever, David Coward, E. Schmidt, Sheon Chua, B. Braginsky, R. Bonnand, J. Woehler, A. K. Zadrożny, T. Derosa, M. van Beuzekom, B. Rei, David A. Nichols, J. Raab, E. M. Fries, Britton D. Smith, A. L. Urban, A. Usman, A. Giaime, L. Sun, A. C. Green, S. Chung, L. Danilishin, Evan Ochsner, W. Z. Korth, D. Hoak, Stefan L. Danilishin, D. Sentenac, A. J. Weinstein, Patrick Brady, J. S. Areeda, L. Trozzo, Priscilla Canizares, L. Swinkels, T. Sadecki, Laleh Sadeghian, R. C. Walet, V. P. Mitrofanov, M. Coward, H. J. Bulten, L. Glover, Fausto Acernese, Albert Lazzarini, M. Bitossi, T. Di Girolamo, M. C. Araya, A. G. Clark, V. Boschi, S. Penn, D. Schuette, A. Ananyeva, M. Landry, M. K. M. Bader, Mi Zhang, C. Gray, G. H. Ogin, T. J. Shaffer, O. J. Piccinni, K. Wette, John J. Oh, Timothy Evans, L. Di Fiore, Xavier Siemens, Jochen Schmidt, S. Grunewald, C. Celestino Silva, W. Del Pozzo, P. F. Cohadon, H. Heitmann, A. Bilenko, C. Affeldt, M. Bawaj, M. Mantovani, P. Mohapatra, R. C. Devine, Christopher M. Biwer, M. Newport, Samaya Nissanke, R. Taylor, S. Frasca, G. L. Mansell, A. Houston, George Hobbs, M. Barsuglia, Enrico Calloni, G. Traylor, V. Dattilo, Edwin J. Son, P. Aufmuth, Thomas Corbitt, M. Lee, Olivier Minazzoli, Chandra Kant Mishra, S. Koley, Amanda J. Page, David Blair, Laura Sampson, J. Perez, R. Bhandare, M. Razzano, Lee McCuller, N. Mazumder, R. T. DeRosa, A. Grant, David Jones, L. Salconi, C. A. Costa, Marco Cavaglia, A. Viceré, Stefan Hild, D. Pascucci, Tiantian Zhang, Y. Ma, A. Possenti, Riccardo Ciolfi, Yi Chen, Athol J. Kemball, Roger Smith, James G. Bartlett, Kazuhiro Agatsuma, Adam A. Libson, Robinjeet Singh, A. Brillet, J. Roma, L. Conti, J. Slagmolen, F. Martelli, Karan Jani, C. Bradaschia, M. Gonzalez Castro, A. Thorne, F. Mezzani, L. Savage, Frank Ohme, M. Tonelli, Ismaël Cognard, Paulo C. C. Freire, Sau Lan Wu, James Healy, L. Pearlstone, S. Bae, B. Mours, P. Mitrofanov, C. Adams, R. M. Blair, D. Sigg, M. Vardaro, A. Post, M. Leonardi, Alessandro Costa, F. Robinet, S. Márka, M. Yvert, T. D. Abbott, O. Puncken, Zoheyr Doctor, Stephen Fairhurst, Carl Blair, E. Coccia, M. E. Zucker, C. Graef, B. A. Weaver, Laura Cadonati, L. Rei, J. G. Rollins, L.-W. Wei, Gijs Nelemans, E. D. Hall, Jolien D. E. Creighton, A. W. Heptonstall, Vivien Raymond, Peter R. Saulson, Archana Pai, P. Brockill, F. Paoletti, G. Vedovato, William Yam, L. Wallace, D. B. Kozak, S. J. Kimbrell, L. Kleybolte, J. Ottaway, P. Ruggi, L. Cerboni Baiardi, M. Kim, Terry G. McRae, S. S. Forsyth, A. Mullavey, T. J. N. Nelson, Kenneth A. Strain, Jimin George, M. Sieniawska, S. W. Ballmer, Gregory Ashton, K. Holt, Chunglee Kim, V. Sandberg, A. Perreca, Fabio Marchesoni, C. Vorvick, Daniel R. George, Kris Ryan, E. A. Quintero, Andrew Lundgren, Susan M. Scott, Y. Wang, A. Królak, R. Frey, Duncan Meacher, M. Macleod, Xiaohui Fan, W. S. Kim, Richard O'Shaughnessy, B. Barr, E. A. Muñiz, T. Denker, Christopher P. L. Berry, A. D. Silva, S. Brunett, Michelle E. Walker, B. Shapiro, Debarati Chatterjee, J. K. Nelson, C. E. Cirelli, Daniele Trifirò, Chad Hanna, T. A. Callister, N. M. Brown, D. S. Rabeling, M. Di Giovanni, K. E. Gushwa, Reinhard Prix, M. Haney, J. Oberling, Rocco Romano, John D. Scott, A. Boom, B. O'Reilly, P. Gruning, Jade Powell, V. Mangano, H-P Cheng, Eric Oelker, R. A. Mercer, J. Jonker, Jinsook Kim, G. Moreno, C. Pant, David H. Reitze, D. N. Brown, Yi-Ming Hu, A. Bisht, A. Staley, F. Nocera, A. Moggi, J. Ming, Michael L. Gorodetsky, T. Westphal, Ryan Lynch, C. Cannon, C. Coyne, G. Stratta, C. C. Yancey, A. Ain, Alicia M. Sintes, W. Tsang, Swetha Bhagwat, Thibaut Jacqmin, Jesper Munch, J. Vine, D. Buskulic, B. Pang, Achamveedu Gopakumar, A. Callister, S. Jawahar, M. De Laurentis, W. G. Anderson, G. Cella, Dwayne D. Giardina, C. I. Torrie, A. K. Lenon, D. C. Coyne, G. Arun, D. Rosińska, Patrice Hello, C-H. Lee, Matthew Evans, Z. Korth, Giacomo Ciani, Richard J. Abbott, K. Izumi, Hartmut Grote, T. Hardwick, D. Steinmeyer, A. F. Brooks, D. R. Ingram, M. Oliver, Douglas Davis, H. Fair, G. Losurdo, B. P. Abbott, M. Mow-Lowry, E. K. Gustafson, Andrea Taracchini, J. V. van Heijningen, G. Cagnoli, O. Bock, Neil J. Cornish, Eric Thrane, T. D. Creighton, P. Lundgren, S. Vass, S. Privitera, F. Travasso, C. Michel, M. Koehlenbeck, Lionel London, Sarah Caudill, R. Inta, S. Karvinen, R. Coyne, V. Loriette, Fabrice Matichard, S. Klimenko, R. Quitzow-James, V. B. Adya, Francesco Salemi, A. Prodi, A. Effler, A. K. Y. Li, G. Gemme, M. Drago, V. Dolique, I. Dorrington, J. Duncan, Steven Reyes, E. K. Wessel, S. D'Antonio, D. Ugolini, Collin D. Capano, P. Pfeiffer, Guenakh Mitselmakher, B. Adya, B. A. Boom, A. M. Sergeev, E. J. Fauchon-Jones, M. Lormand, J. Massinger, M. Prijatelj, J. Warner, S. B. Coughlin, Jessica Steinlechner, H. Rew, R. Passaquieti, Alexander H. Nitz, C. Rajan, A. Neunzert, J. Bulten, Debnandini Mukherjee, T. Chmiel, M. Heurs, J-Y. Vinet, Reed Essick, G. A. Prodi, R. DeSalvo, S. Kandhasamy, B. Sorazu, D Shoemaker, O. V. Palashov, Sean T. McWilliams, F. Piergiovanni, S. Doravari, L. Lo, J. Cullen, A. Kutynia, T. T. Nguyen, Andrea Chincarini, T. Z. Summerscales, Innocenzo M. Pinto, M. Davier, P. G. Murray, B. Kozak, B. K. Berger, Fabien Kéfélian, J. H. Hough, P. W. F. Forsyth, J. R. Palamos, Michele Zanolin, T. J. Massinger, T. Vo, V. Kalogera, G. D. Hammond, L. Sammut, L. Kuo, H. Yamamoto, E. Capocasa, A. Schönbeck, J. Prasad, Steven Bloemen, Jonathan R. Gair, L. M. Perri, N. A. Lockerbie, Blake Moore, Carlos O. Lousto, Kishora Nayak, Thomas Dent, P. Corban, Vladimir Dergachev, C. Barish, James Whelan, P. Ajith, Andrew Lyne, M. Gabel, Zhihui Du, S. S. Eikenberry, Rosa Poggiani, V. Frey, S. Farinon, P. Raffai, J. Hanks, J. D. Lough, Soma Mukherjee, A. Mercer, H. R. Paris, A. Eisenstein, P. Kumar, B. R. Hall, A. Shaddock, R. Cavalieri, A. K. Srivastava, A. E. Pace, E. G. Thomas, A. Basti, Ryan N. Lang, Jens Birch, Z. Frei, V. Sequino, S. Caride, J.-D. Fournier, Philip F. Hopkins, I. Fiori, J. P. Henry, P. Vyatchanin, M. F. Carney, John Worden, P. Couvares, Archisman Ghosh, Jan Harms, A. S. Sengupta, Satyanarayan Ray Pitambar Mohapatra, Sascha Husa, Matthew Kerr, G. Venugopalan, Meng Wang, D.B. DeBra, Evan Goetz, Aniello Grado, J. M. Newport, T. Theeg, E. Cuoco, A. Gupta, S. Meshkov, Seog Oh, K. G. Arun, X. Guo, K. Siellez, A. Vo, P. Bacon, Daniel E. Holz, P. J. Veitch, B. Patricelli, D. S. Wu, Margaret Millhouse, S. G. Gaonkar, P. Cheng, Haixing Miao, G. Bogaert, L. Wright, K. L. Dooley, Lisa Barsotti, Anirban Dasgupta, K. Venkateswara, P. Zendri, Yuri Levin, Robert Stone, R. J. G. Jonker, M. Isac, A. R. Williamson, A. Cumming, F. Di Renzo, Albrecht Rüdiger, Xing-Jiang Zhu, E. Genin, R. A. Eisenstein, B. J. J. Slagmolen, Hee-Suk Cho, Benjamin Stappers, G. D. Meadors, T. Zelenova, Riccardo Bassiri, Magnus Manske, S. Qiu, E. Maros, A. Lockerbie, F. Baldaccini, L. F. Ortega, M. J. Hart, J. K. Blackburn, A. Sawadsky, E. Chassande-Mottin, Sheila Rowan, S. Kwang, Todd Adams, Felice Sorrentino, D. Moraru, Giuseppe Intini, A. Allocca, F. Vetrano, S. Antier, M. Dovale Álvarez, H. Reitze, S. E. Dwyer, David Keitel, S. J. Cooper, A. Lartaux-Vollard, Suvadeep Bose, R. Gouaty, Z. Márka, Andrew Robertson, B. Lantz, L. Romel, W. Katzman, L. van der Schaaf, S. A. Pai, Cody Messick, C. Whittle, Milan Gupta, C. Kent, G. Mendell, J. Trinastic, M. Ducrot, M. Merzougui, Rebecca Fisher, J. Eichholz, G. P. Newton, A. Bohe, M. Fyffe, Gabriela Gonzalez, K. R. Corley, L. Ward, A.M. Taylor, J. Junker, I. Belahcene, Tania Regimbau, M. M. Hanke, W. Parker, S. B. Anderson, C. Devine, Zachariah B. Etienne, Jennifer Watchi, J. Son, C. Buy, C. Essick, T. P. Downes, P. H. Fisher, M. Pedraza, E. Cesarini, M. Chan, Maria Alessandra Papa, F. Cavalier, N. Bode, Ian P. Jones, J. L. Wright, Alessandra Corsi, J. E. Lord, E. J. Daw, Maurizio Canepa, Paolo Addesso, K. D. Giardina, J. K. Wofford, M. A. Page, Francesco Pannarale, J. S. Lange, A. Rocchi, N. A. Robertson, C. Cocchieri, R. Birney, R. M. S. Schofield, Márton Tápai, David Jonathan Hofman, S. Kissel, Liam Cunningham, A. Noack, Jonathan Blackman, Benjamin J. Owen, G.A. Blair, J. F. J. van den Brand, K. Toland, D. Tuyenbayev, S. Sunil, M. Tacca, Martin Hendry, M. C. Díaz, J. H. Howell, K. V. Tokmakov, Maria Ilaria Del Principe, M. Agathos, C. Horst, Antonios Kontos, Alberto Vecchio, S. Kim, L. Prokhorov, Will M. Farr, Junwei Cao, M. Montani, Nancy Aggarwal, Zahoor Ali Khan, A. Papa, C. Stephens, S. Thorne, L. Dooley, I. Dave, H. Lee, Graham Woan, Robert L. Byer, M. Fletcher, B. Hughey, Stuart Reid, G. Valdes, A. Samajdar, S. Rieger, S. Unnikrishnan, Jacob Scheuer, J. Piccinni, Phil D. C. King, M. Pinto, J.-P. Zendri, Bernard F. Schutz, S. E. Gossan, L. Merilh, Li Ju, Daniel A. Shaddock, C. V. Kalaghatgi, J. Hanson, K. Napier, Guido Mueller, A. Miller, Hang Yu, Michael J. I. Brown, P. Fulda, S. E. Barclay, Ofek Birnholtz, K. Gustafson, Eric Howell, S. Leavey, M. Katolik, L. K. Nuttall, G. Billingsley, S. Macfoy, B. B. Miller, Z. Summerscales, Jong H. Chow, J. Liu, A. Pasqualetti, LIGO, Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL), Department of Physics [Toronto], University of Toronto, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Paul Scherrer Institute (PSI), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (AEI), Max-Planck-Gesellschaft, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Department of Physics, Columbia University [New York], Dipartimento di Physica E. Firmi, University of Pisa - Università di Pisa, Max-Planck-Institut für Gravitationsphysik ( Albert-Einstein-Institut ) (AEI), Copernicus Astronomical Center of the Polish Academy of Sciences (CAMK), Polish Academy of Sciences (PAN), Association de Coordination Technique Agricole (ACTA), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), LAboratoire de REcherche en Géodésie [Paris] (LAREG), Laboratoire des Sciences et Technologies de l'Information Géographique (LaSTIG), École nationale des sciences géographiques (ENSG), Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Institut National de l'Information Géographique et Forestière [IGN] (IGN)-École nationale des sciences géographiques (ENSG), Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Institut National de l'Information Géographique et Forestière [IGN] (IGN), Astrophysique Relativiste Théories Expériences Métrologie Instrumentation Signaux (ARTEMIS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des matériaux avancés (LMA), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Kastler Brossel (LKB (Jussieu)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Science and Engineering Research Board, Royal Society, Australian Research Council, Narodowe Centrum Nauki, Scottish Universities Physics Alliance, Centre National de la Recherche Scientifique, National Science Foundation, Ministry of Science and Technology of the People's Republic of China, Russian Foundation for Basic Research, Conselleria d’Economia i Competitivitat and Conselleria d’Educació, Cultura i Universitats of the Govern de les Illes Balears, Natural Sciences and Engineering Research Council of Canada, Lyon Institute of Origins, Ministry of Human Resource Development, Kavli Foundation, Research Corporation for Science Advancement, European Commission, Instituto Nazionale di Fisica Nucleare, National Research Foundation of Korea, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Ministério da Ciência, Tecnologia e Inovação, Canadian Institute for Advanced Research, Science and Technology Facilities Council, Leverhulme Trust, Ontario Ministry of Economic Development and Innovation, Ministerio de Economía y Competitividad, Scottish Funding Council, Fundação de Amparo à Pesquisa do Estado de São Paulo, Országos Tudományos Kutatási Alapprogramok, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Les instituts techniques agricoles (Acta), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Ecole Supérieure de Physique et de Chimie Industrielles (ESPCI), Mairie de Paris, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Albert Einstein Institute, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), APC - Cosmologie, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), APC - THEORIE, Institut für theoretische Physik, Universität Hamburg (UHH)-Universität Hamburg (UHH)-AstroParticule et Cosmologie (APC (UMR_7164)), Met Office Hadley Centre (MOHC), Abbott, B. P., Abbott, R., Abbott, T. D., Acernese, F., Ackley, K., Adams, C., Adams, T., Addesso, P., Adhikari, R. X., Adya, V. B., Affeldt, C., Afrough, M., Agarwal, B., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O. D., Aiello, L., Ain, A., Ajith, P., Allen, G., Allocca, A., Altin, P. A., Amato, A., Ananyeva, A., Anderson, S. B., Anderson, W. G., Antier, S., Appert, S., Arai, K., Araya, M. C., Areeda, J. S., Arnaud, N., Arun, K. G., Ascenzi, S., Ashton, G., Ast, M., Aston, S. M., Astone, P., Aufmuth, P., Aulbert, C., Aultoneal, K., Avila-Alvarez, A., Babak, S., Bacon, P., Bader, M. K. M., Bae, S., Baker, P. T., Baldaccini, F., Ballardin, G., Ballmer, S. W., Banagiri, S., Barayoga, J. C., Barclay, S. E., Barish, B. C., Barker, D., Barone, F., Barr, B., Barsotti, L., Barsuglia, M., Barta, D., Bartlett, J., Bartos, I., Bassiri, R., Basti, A., Batch, J. C., Baune, C., Bawaj, M., Bazzan, M., Bécsy, B., Beer, C., Bejger, M., Belahcene, I., Bell, A. S., Berger, B. K., Bergmann, G., Berry, C. P. L., Bersanetti, D., Bertolini, A., Betzwieser, J., Bhagwat, S., Bhandare, R., Bilenko, I. A., Billingsley, G., Billman, C. R., Birch, J., Birney, R., Birnholtz, O., Biscans, S., Bisht, A., Bitossi, M., Biwer, C., Bizouard, M. A., Blackburn, J. K., Blackman, J., Blair, C. D., Blair, D. G., Blair, R. M., Bloemen, S., Bock, O., Bode, N., Boer, M., Bogaert, G., Bohe, A., Bondu, F., Bonnand, R., Boom, B. A., Bork, R., Boschi, V., Bose, S., Bouffanais, Y., Bozzi, A., Bradaschia, C., Brady, P. R., Braginsky, V. B., Branchesi, M., Brau, J. E., Briant, T., Brillet, A., Brinkmann, M., Brisson, V., Brockill, P., Broida, J. E., Brooks, A. F., Brown, D. A., Brown, D. D., Brown, N. M., Brunett, S., Buchanan, C. C., Buikema, A., Bulik, T., Bulten, H. J., Buonanno, A., Buskulic, D., Buy, C., Byer, R. L., Cabero, M., Cadonati, L., Cagnoli, G., Cahillane, C., Calderón Bustillo, J., Callister, T. A., Calloni, E., Camp, J. B., Canepa, M., Canizares, P., Cannon, K. C., Cao, H., Cao, J., Capano, C. D., Capocasa, E., Carbognani, F., Caride, S., Carney, M. F., Casanueva Diaz, J., Casentini, C., Caudill, S., Cavaglià, M., Cavalier, F., Cavalieri, R., Cella, G., Cepeda, C. B., Cerboni Baiardi, L., Cerretani, G., Cesarini, E., Chamberlin, S. J., Chan, M., Chao, S., Charlton, P., Chassande-Mottin, E., Chatterjee, D., Cheeseboro, B. D., Chen, H. Y., Chen, Y., Cheng, H. -P., Chincarini, A., Chiummo, A., Chmiel, T., Cho, H. S., Cho, M., Chow, J. H., Christensen, N., Chu, Q., Chua, A. J. K., Chua, S., Chung, A. K. W., Chung, S., Ciani, G., Ciolfi, R., Cirelli, C. E., Cirone, A., Clara, F., Clark, J. A., Cleva, F., Cocchieri, C., Coccia, E., Cohadon, P. -F., Colla, A., Collette, C. G., Cominsky, L. R., Constancio, M., Conti, L., Cooper, S. J., Corban, P., Corbitt, T. R., Corley, K. R., Cornish, N., Corsi, A., Cortese, S., Costa, C. A., Coughlin, M. W., Coughlin, S. B., Coulon, J. -P., Countryman, S. T., Couvares, P., Covas, P. B., Cowan, E. E., Coward, D. M., Cowart, M. J., Coyne, D. C., Coyne, R., Creighton, J. D. E., Creighton, T. D., Cripe, J., Crowder, S. G., Cullen, T. J., Cumming, A., Cunningham, L., Cuoco, E., Canton, T. Dal, Danilishin, S. L., D'Antonio, S., Danzmann, K., Dasgupta, A., Da Silva Costa, C. F., Dattilo, V., Dave, I., Davier, M., Davis, D., Daw, E. J., Day, B., De, S., Debra, D., Degallaix, J., De Laurentis, M., Deléglise, S., Del Pozzo, W., Denker, T., Dent, T., Dergachev, V., De Rosa, Rosario., Derosa, R. T., Desalvo, R., Devenson, J., Devine, R. C., Dhurandhar, S., Díaz, M. C., Di Fiore, L., Di Giovanni, M., Di Girolamo, T., Di Lieto, A., Di Pace, S., Di Palma, I., Di Renzo, F., Doctor, Z., Dolique, V., Donovan, F., Dooley, K. L., Doravari, S., Dorrington, I., Douglas, R., Dovale Álvarez, M., Downes, T. P., Drago, M., Drever, R. W. P., Driggers, J. C., Du, Z., Ducrot, M., Duncan, J., Dwyer, S. E., Edo, T. B., Edwards, M. C., Effler, A., Eggenstein, H. -B., Ehrens, P., Eichholz, J., Eikenberry, S. S., Eisenstein, R. A., Essick, R. C., Etienne, Z. B., Etzel, T., Evans, M., Evans, T. M., Factourovich, M., Fafone, V., Fair, H., Fairhurst, S., Fan, X., Farinon, S., Farr, B., Farr, W. M., Fauchon-Jones, E. J., Favata, M., Fays, M., Fehrmann, H., Feicht, J., Fejer, M. M., Fernandez-Galiana, A., Ferrante, I., Ferreira, E. C., Ferrini, F., Fidecaro, F., Fiori, I., Fiorucci, D., Fisher, R. P., Flaminio, R., Fletcher, M., Fong, H., Forsyth, P. W. F., Forsyth, S. S., Fournier, J. -D., Frasca, S., Frasconi, F., Frei, Z., Freise, A., Frey, R., Frey, V., Fries, E. M., Fritschel, P., Frolov, V. V., Fulda, P., Fyffe, M., Gabbard, H., Gabel, M., Gadre, B. U., Gaebel, S. M., Gair, J. R., Gammaitoni, L., Ganija, M. R., Gaonkar, S. G., Garufi, F., Gaudio, S., Gaur, G., Gayathri, V., Gehrels, N., Gemme, G., Genin, E., Gennai, A., George, D., George, J., Gergely, L., Germain, V., Ghonge, S., Ghosh, Abhirup, Ghosh, Archisman, Ghosh, S., Giaime, J. A., Giardina, K. D., Giazotto, A., Gill, K., Glover, L., Goetz, E., Goetz, R., Gomes, S., González, G., Gonzalez Castro, J. M., Gopakumar, A., Gorodetsky, M. L., Gossan, S. E., Gosselin, M., Gouaty, R., Grado, A., Graef, C., Granata, M., Grant, A., Gras, S., Gray, C., Greco, G., Green, A. C., Groot, P., Grote, H., Grunewald, S., Gruning, P., Guidi, G. M., Guo, X., Gupta, A., Gupta, M. K., Gushwa, K. E., Gustafson, E. K., Gustafson, R., Hall, B. R., Hall, E. D., Hammond, G., Haney, M., Hanke, M. M., Hanks, J., Hanna, C., Hannuksela, O. A., Hanson, J., Hardwick, T., Harms, J., Harry, G. M., Harry, I. W., Hart, M. J., Haster, C. -J., Haughian, K., Healy, J., Heidmann, A., Heintze, M. C., Heitmann, H., Hello, P., Hemming, G., Hendry, M., Heng, I. S., Hennig, J., Henry, J., Heptonstall, A. W., Heurs, M., Hild, S., Hoak, D., Hofman, D., Holt, K., Holz, D. E., Hopkins, P., Horst, C., Hough, J., Houston, E. A., Howell, E. J., Hu, Y. M., Huerta, E. A., Huet, D., Hughey, B., Husa, S., Huttner, S. H., Huynh-Dinh, T., Indik, N., Ingram, D. R., Inta, R., Intini, G., Isa, H. N., Isac, J. -M., Isi, M., Iyer, B. R., Izumi, K., Jacqmin, T., Jani, K., Jaranowski, P., Jawahar, S., Jiménez-Forteza, F., Johnson, W. W., Jones, D. I., Jones, R., Jonker, R. J. G., Ju, L., Junker, J., Kalaghatgi, C. V., Kalogera, V., Kandhasamy, S., Kang, G., Kanner, J. B., Karki, S., Karvinen, K. S., Kasprzack, M., Katolik, M., Katsavounidis, E., Katzman, W., Kaufer, S., Kawabe, K., Kéfélian, F., Keitel, D., Kemball, A. J., Kennedy, R., Kent, C., Key, J. S., Khalili, F. Y., Khan, I., Khan, S., Khan, Z., Khazanov, E. A., Kijbunchoo, N., Kim, Chunglee, Kim, J. C., Kim, W., Kim, W. S., Kim, Y. -M., Kimbrell, S. J., King, E. J., King, P. J., Kirchhoff, R., Kissel, J. S., Kleybolte, L., Klimenko, S., Koch, P., Koehlenbeck, S. M., Koley, S., Kondrashov, V., Kontos, A., Korobko, M., Korth, W. Z., Kowalska, I., Kozak, D. B., Krämer, C., Kringel, V., Krishnan, B., Królak, A., Kuehn, G., Kumar, P., Kumar, R., Kumar, S., Kuo, L., Kutynia, A., Kwang, S., Lackey, B. D., Lai, K. H., Landry, M., Lang, R. N., Lange, J., Lantz, B., Lanza, R. K., Lartaux-Vollard, A., Lasky, P. D., Laxen, M., Lazzarini, A., Lazzaro, C., Leaci, P., Leavey, S., Lee, C. H., Lee, H. K., Lee, H. M., Lee, H. W., Lee, K., Lehmann, J., Lenon, A., Leonardi, M., Leroy, N., Letendre, N., Levin, Y., Li, T. G. F., Libson, A., Littenberg, T. B., Liu, J., Lo, R. K. L., Lockerbie, N. A., London, L. T., Lord, J. E., Lorenzini, M., Loriette, V., Lormand, M., Losurdo, G., Lough, J. D., Lousto, C. O., Lovelace, G., Lück, H., Lumaca, D., Lundgren, A. P., Lynch, R., Ma, Y., Macfoy, S., Machenschalk, B., Macinnis, M., Macleod, D. M., Magaña Hernandez, I., Magaña-Sandoval, F., Magaña Zertuche, L., Magee, R. M., Majorana, E., Maksimovic, I., Man, N., Mandic, V., Mangano, V., Mansell, G. L., Manske, M., Mantovani, M., Marchesoni, F., Marion, F., Márka, S., Márka, Z., Markakis, C., Markosyan, A. S., Maros, E., Martelli, F., Martellini, L., Martin, I. W., Martynov, D. V., Mason, K., Masserot, A., Massinger, T. J., Masso-Reid, M., Mastrogiovanni, S., Matas, A., Matichard, F., Matone, L., Mavalvala, N., Mazumder, N., Mccarthy, R., Mcclelland, D. E., Mccormick, S., Mcculler, L., Mcguire, S. C., Mcintyre, G., Mciver, J., Mcmanus, D. J., Mcrae, T., Mcwilliams, S. T., Meacher, D., Meadors, G. D., Meidam, J., Mejuto-Villa, E., Melatos, A., Mendell, G., Mercer, R. A., Merilh, E. L., Merzougui, M., Meshkov, S., Messenger, C., Messick, C., Metzdorff, R., Meyers, P. M., Mezzani, F., Miao, H., Michel, C., Middleton, H., Mikhailov, E. E., Milano, L., Miller, A. L., Miller, A., Miller, B. B., Miller, J., Millhouse, M., Minazzoli, O., Minenkov, Y., Ming, J., Mishra, C., Mitra, S., Mitrofanov, V. P., Mitselmakher, G., Mittleman, R., Moggi, A., Mohan, M., Mohapatra, S. R. P., Montani, M., Moore, B. C., Moore, C. J., Moraru, D., Moreno, G., Morriss, S. R., Mours, B., Mow-Lowry, C. M., Mueller, G., Muir, A. W., Mukherjee, Arunava, Mukherjee, D., Mukherjee, S., Mukund, N., Mullavey, A., Munch, J., Muniz, E. A. M., Murray, P. G., Napier, K., Nardecchia, I., Naticchioni, L., Nayak, R. K., Nelemans, G., Nelson, T. J. N., Neri, M., Nery, M., Neunzert, A., Newport, J. M., Newton, G., Ng, K. K. Y., Nguyen, T. T., Nichols, D., Nielsen, A. B., Nissanke, S., Nitz, A., Noack, A., Nocera, F., Nolting, D., Normandin, M. E. N., Nuttall, L. K., Oberling, J., Ochsner, E., Oelker, E., Ogin, G. H., Oh, J. J., Oh, S. H., Ohme, F., Oliver, M., Oppermann, P., Oram, Richard J., O'Reilly, B., Ormiston, R., Ortega, L. F., O'Shaughnessy, R., Ottaway, D. J., Overmier, H., Owen, B. J., Pace, A. E., Page, J., Page, M. A., Pai, A., Pai, S. A., Palamos, J. R., Palashov, O., Palomba, C., Pal-Singh, A., Pan, H., Pang, B., Pang, P. T. H., Pankow, C., Pannarale, F., Pant, B. C., Paoletti, F., Paoli, A., Papa, M. A., Paris, H. R., Parker, W., Pascucci, D., Pasqualetti, A., Passaquieti, R., Passuello, D., Patricelli, B., Pearlstone, B. L., Pedraza, M., Pedurand, R., Pekowsky, L., Pele, A., Penn, S., Perez, C. J., Perreca, A., Perri, L. M., Pfeiffer, H. P., Phelps, M., Piccinni, O. J., Pichot, M., Piergiovanni, F., Pierro, V., Pillant, G., Pinard, L., Pinto, I. M., Pitkin, M., Poggiani, R., Popolizio, P., Porter, E. K., Post, A., Powell, J., Prasad, J., Pratt, J. W. W., Predoi, V., Prestegard, T., Prijatelj, M., Principe, M., Privitera, S., Prix, R., Prodi, G. A., Prokhorov, L. G., Puncken, O., Punturo, M., Puppo, P., Pürrer, M., Qi, H., Qin, J., Qiu, S., Quetschke, V., Quintero, E. A., Quitzow-James, R., Raab, F. J., Rabeling, D. S., Radkins, H., Raffai, P., Raja, S., Rajan, C., Rakhmanov, M., Ramirez, K. E., Rapagnani, P., Raymond, V., Razzano, M., Read, J., Regimbau, T., Rei, L., Reid, S., Reitze, D. H., Rew, H., Reyes, S. D., Ricci, F., Ricker, P. M., Rieger, S., Riles, K., Rizzo, M., Robertson, N. A., Robie, R., Robinet, F., Rocchi, A., Rolland, L., Rollins, J. G., Roma, V. J., Romano, R., Romel, C. L., Romie, J. H., Rosińska, D., Ross, M. P., Rowan, S., Rüdiger, A., Ruggi, P., Ryan, K., Sachdev, S., Sadecki, T., Sadeghian, L., Sakellariadou, M., Salconi, L., Saleem, M., Salemi, F., Samajdar, A., Sammut, L., Sampson, L. M., Sanchez, E. J., Sandberg, V., Sandeen, B., Sanders, J. R., Sassolas, B., Sathyaprakash, B. S., Saulson, P. R., Sauter, O., Savage, R. L., Sawadsky, A., Schale, P., Scheuer, J., Schmidt, E., Schmidt, J., Schmidt, P., Schnabel, R., Schofield, R. M. S., Schönbeck, A., Schreiber, E., Schuette, D., Schulte, B. W., Schutz, B. F., Schwalbe, S. G., Scott, J., Scott, S. M., Seidel, E., Sellers, D., Sengupta, A. S., Sentenac, D., Sequino, V., Sergeev, A., Shaddock, D. A., Shaffer, T. J., Shah, A. A., Shahriar, M. S., Shao, L., Shapiro, B., Shawhan, P., Sheperd, A., Shoemaker, D. H., Shoemaker, D. M., Siellez, K., Siemens, X., Sieniawska, M., Sigg, D., Silva, A. D., Singer, A., Singer, L. P., Singh, A., Singh, R., Singhal, A., Sintes, A. M., Slagmolen, B. J. J., Smith, B., Smith, J. R., Smith, R. J. E., Son, E. J., Sonnenberg, J. A., Sorazu, B., Sorrentino, F., Souradeep, T., Spencer, A. P., Srivastava, A. K., Staley, A., Steinke, M., Steinlechner, J., Steinlechner, S., Steinmeyer, D., Stephens, B. C., Stone, R., Strain, K. A., Stratta, G., Strigin, S. E., Sturani, R., Stuver, A. L., Summerscales, T. Z., Sun, L., Sunil, S., Sutton, P. J., Swinkels, B. L., Szczepańczyk, M. J., Tacca, M., Talukder, D., Tanner, D. B., Tápai, M., Taracchini, A., Taylor, J. A., Taylor, R., Theeg, T., Thomas, E. G., Thomas, M., Thomas, P., Thorne, K. A., Thorne, K. S., Thrane, E., Tiwari, S., Tiwari, V., Tokmakov, K. V., Toland, K., Tonelli, M., Tornasi, Z., Torrie, C. I., Töyrä, D., Travasso, F., Traylor, G., Trifirò, D., Trinastic, J., Tringali, M. C., Trozzo, L., Tsang, K. W., Tse, M., Tso, R., Tuyenbayev, D., Ueno, K., Ugolini, D., Unnikrishnan, C. S., Urban, A. L., Usman, S. A., Vahlbruch, H., Vajente, G., Valdes, G., Vallisneri, M., Van Bakel, N., Van Beuzekom, M., Van Den Brand, J. F. J., Van Den Broeck, C., Vander-Hyde, D. C., Van Der Schaaf, L., Van Heijningen, J. V., Van Veggel, A. A., Vardaro, M., Varma, V., Vass, S., Vasúth, M., Vecchio, A., Vedovato, G., Veitch, J., Veitch, P. J., Venkateswara, K., Venugopalan, G., Verkindt, D., Vetrano, F., Viceré, A., Viets, A. D., Vinciguerra, S., Vine, D. J., Vinet, J. -Y., Vitale, S., Vo, T., Vocca, H., Vorvick, C., Voss, D. V., Vousden, W. D., Vyatchanin, S. P., Wade, A. R., Wade, L. E., Wade, M., Walet, R., Walker, M., Wallace, L., Walsh, S., Wang, G., Wang, H., Wang, J. Z., Wang, M., Wang, Y. -F., Wang, Y., Ward, R. L., Warner, J., Was, M., Watchi, J., Weaver, B., Wei, L. -W., Weinert, M., Weinstein, A. J., Weiss, R., Wen, L., Wessel, E. K., Weßels, P., Westphal, T., Wette, K., Whelan, J. T., Whiting, B. F., Whittle, C., Williams, D., Williams, R. D., Williamson, A. R., Willis, J. L., Willke, B., Wimmer, M. H., Winkler, W., Wipf, C. C., Wittel, H., Woan, G., Woehler, J., Wofford, J., Wong, K. W. K., Worden, J., Wright, J. L., Wu, D. S., Wu, G., Yam, W., Yamamoto, H., Yancey, C. C., Yap, M. J., Yu, Hang, Yu, Haocun, Yvert, M., Zadrożny, A., Zanolin, M., Zelenova, T., Zendri, J. -P., Zevin, M., Zhang, L., Zhang, M., Zhang, T., Zhang, Y. -H., Zhao, C., Zhou, M., Zhou, Z., Zhu, S. J., Zhu, X. J., Zucker, M. E., Zweizig, J., Buchner, S., Cognard, I., Corongiu, A., Freire, P. C. C., Guillemot, L., Hobbs, G. B., Kerr, M., Lyne, A. G., Possenti, A., Ridolfi, A., Shannon, R. M., Stappers, B. W., Weltevrede, P., The LIGO Scientific Collaboration, The Virgo Collaboration, and (Astro)-Particles Physics

Subjects
Gravitational-wave observatory, Astronomy, Speed of gravity, General Physics and Astronomy, Tensors, stochastic gravitational-wave, 01 natural sciences, General Relativity and Quantum Cosmology, Strain, Gravitational field, gravitational waves, LIGO, Linearized gravity, Directed searches, TOOL, Theory of gravity, QC, QB, Physics, [PHYS]Physics [physics], non-tensorial, Gravitational effects, article, Rotational frequency, Upper limits, Classical mechanics, Gravitational redshift, General Relativity, General relativity, Gravitational waves, pulsars, non-tensorial, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Gravity waves, Gravitational waves, Relativity, Physics and Astronomy (all), 0103 physical sciences, ddc:530, Tensor polarization, 010306 general physics, Pulsars, polarization, 010308 nuclear & particles physics, Gravitational wave, 530 Physik, Nonsymmetric gravitational theory, gravity, Physics and Astronomy, [SDU]Sciences of the Universe [physics], Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously-published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity., Comment: journal version

Published
2018
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47. The NANOGrav 11-Year Data Set: Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries

Author

David L. Kaplan, Adam Brazier, Sarah Burke-Spolaor, Megan E. DeCesar, Emmanuel Fonseca, R. van Haasteren, Joseph Simon, Joey Shapiro Key, Robert D. Ferdman, Cherry Ng, Zaven Arzoumanian, Lina Levin, Peter A. Gentile, N. Garver-Daniels, Neil J. Cornish, Ryan S. Lynch, Chiara M. F. Mingarelli, A. M. Holgado, Xavier Siemens, Kathryn Crowter, Justin A. Ellis, Stephen Taylor, J. E. Turner, Weiwei Zhu, Caitlin A. Witt, Ingrid H. Stairs, Paul Demorest, T. J. W. Lazio, Paul S. Ray, Michele Vallisneri, Ross J. Jennings, K. Islo, E. A. Huerta, J. Luo, Luke Zoltan Kelley, Sean T. McWilliams, David J. Nice, Maura McLaughlin, D. R. Madison, Daniel R. Stinebring, James M. Cordes, Renée Spiewak, P. T. Baker, M. R. Brinson, Kshitij Aggarwal, Elizabeth C. Ferrara, Nihan Pol, M. L. Jones, Glenn Jones, Paul R. Brook, Timothy Dolch, Jeffrey S. Hazboun, Scott M. Ransom, Michael T. Lam, Joseph K. Swiggum, H. T. Cromartie, Fronefield Crawford, Duncan R. Lorimer, Shami Chatterjee, Kevin Stovall, Andrew R. Kaiser, Timothy T. Pennucci, and Sarah J. Vigeland

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, General Relativity and Quantum Cosmology, Pulsar, Observatory, 0103 physical sciences, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Supermassive black hole, Solar mass, Gravitational wave, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Virgo Cluster, Galaxy, Black hole, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Observations indicate that nearly all galaxies contain supermassive black holes (SMBHs) at their centers. When galaxies merge, their component black holes form SMBH binaries (SMBHBs), which emit low-frequency gravitational waves (GWs) that can be detected by pulsar timing arrays (PTAs). We have searched the recently-released North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 11-year data set for GWs from individual SMBHBs in circular orbits. As we did not find strong evidence for GWs in our data, we placed 95\% upper limits on the strength of GWs from such sources as a function of GW frequency and sky location. We placed a sky-averaged upper limit on the GW strain of $h_0 < 7.3(3) \times 10^{-15}$ at $f_\mathrm{gw}= 8$ nHz. We also developed a technique to determine the significance of a particular signal in each pulsar using ``dropout' parameters as a way of identifying spurious signals in measurements from individual pulsars. We used our upper limits on the GW strain to place lower limits on the distances to individual SMBHBs. At the most-sensitive sky location, we ruled out SMBHBs emitting GWs with $f_\mathrm{gw}= 8$ nHz within 120 Mpc for $\mathcal{M} = 10^9 \, M_\odot$, and within 5.5 Gpc for $\mathcal{M} = 10^{10} \, M_\odot$. We also determined that there are no SMBHBs with $\mathcal{M} > 1.6 \times 10^9 \, M_\odot$ emitting GWs in the Virgo Cluster. Finally, we estimated the number of potentially detectable sources given our current strain upper limits based on galaxies in Two Micron All-Sky Survey (2MASS) and merger rates from the Illustris cosmological simulation project. Only 34 out of 75,000 realizations of the local Universe contained a detectable source, from which we concluded it was unsurprising that we did not detect any individual sources given our current sensitivity to GWs., 10 pages, 11 figures. Accepted by Astrophysical Journal. Please send any comments/questions to S. J. Vigeland (vigeland@uwm.edu)

Published
2018
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48. Solar System Ephemerides, Pulsar Timing, Gravitational Waves, and Navigation

Author

S. Bhaskaran, W. M. Folkner, T. Joseph W. Lazio, J. A. Ellis, Curt Cutler, Michele Vallisneri, Ryan S. Park, Stephen Taylor, and Todd A. Ely

Subjects
Solar System, Cosmology and Nongalactic Astrophysics (astro-ph.CO), 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Ephemeris, 01 natural sciences, Pulsar, Millisecond pulsar, 0103 physical sciences, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Supermassive black hole, Gravitational wave, Astronomy, Astronomy and Astrophysics, Black hole, Orbit, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

In-spiraling supermassive black holes should emit gravitational waves, which would produce characteristic distortions in the time of arrival residuals from millisecond pulsars. Multiple national and regional consortia have constructed pulsar timing arrays by precise timing of different sets of millisecond pulsars. An essential aspect of precision timing is the transfer of the times of arrival to a (quasi-)inertial frame, conventionally the solar system barycenter. The barycenter is determined from the knowledge of the planetary masses and orbits, which has been refined over the past 50 years by multiple spacecraft. Within the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), uncertainties on the solar system barycenter are emerging as an important element of the NANOGrav noise budget. We describe what is known about the solar system barycenter, touch upon how uncertainties in it affect gravitational wave studies with pulsar timing arrays, and consider future trends in spacecraft navigation., Comment: Four pages, 3 figures; to appear in the proceedings of IAU Symposium 337: Pulsar Astrophysics - The Next 50 Years, eds. P. Weltevrede, B. B. P. Perera, L. Levin Preston & S. Sanidas; see also http://ssd.jpl.nasa.gov/ and arXiv:1801.02617

Published
2018
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49. The NANOGrav 11-year Data Set: High-precision timing of 45 Millisecond Pulsars

Author

Chiara M. F. Mingarelli, Megan E. DeCesar, Weiwei Zhu, Sean T. McWilliams, Emmanuel Fonseca, A. M. Matthews, David J. Nice, Fredrick A. Jenet, Paul Demorest, Joseph K. Swiggum, Andrea N. Lommen, Lina Levin, T. Joseph W. Lazio, Timothy T. Pennucci, Michael T. Lam, Renée Spiewak, Justin A. Ellis, Elizabeth C. Ferrara, Maura McLaughlin, Scott M. Ransom, Timothy Dolch, Ryan S. Lynch, D. R. Madison, Duncan R. Lorimer, Glenn Jones, Rutger van Haasteren, H. Thankful Cromartie, Michele Vallisneri, Ingrid H. Stairs, James M. Cordes, S. J. Chamberlin, Fronefield Crawford, Nathan Garver-Daniels, Stephen Taylor, Kathryn Crowter, Shami Chatterjee, Megan L. Jones, Paul S. Ray, Kevin Stovall, E. A. Huerta, Jing Luo, Robert D. Ferdman, B. Christy, Cherry Ng, Sarah J. Vigeland, Xavier Siemens, Cody Jessup, Daniel Halmrast, Daniel R. Stinebring, Peter A. Gentile, Sarah Burke-Spolaor, David L. Kaplan, Adam Brazier, Neil J. Cornish, Joseph Simon, and Zaven Arzoumanian

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Orbital elements, Physics, 010308 nuclear & particles physics, Gravitational wave, Astrophysics::High Energy Astrophysical Phenomena, Green Bank Telescope, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Shapiro delay, Pulsar, Space and Planetary Science, Observatory, Millisecond pulsar, 0103 physical sciences, Arecibo Observatory, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics
Abstract

We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project, aimed at detecting and characterizing low-frequency gravitational waves. The pulsars were observed with the Arecibo Observatory and/or the Green Bank Telescope at frequencies ranging from 327 MHz to 2.3 GHz. Most pulsars were observed with approximately monthly cadence, with six high--timing-precision pulsars observed weekly, and all were observed at widely separated frequencies at each observing epoch in order to fit for time-variable dispersion delays. We describe our methods for data processing, time-of-arrival (TOA) calculation, and the implementation of a new, automated method for removing outlier TOAs. We fit a timing model for each pulsar that includes spin, astrometric, and, if necessary, binary parameters, in addition to time-variable dispersion delays and parameters that quantify pulse-profile evolution with frequency. The new timing solutions provide three new parallax measurements, two new Shapiro delay measurements, and two new measurements of large orbital-period variations. We fit models that characterize sources of noise for each pulsar. We find that 11 pulsars show significant red noise, with generally smaller spectral indices than typically measured for non-recycled pulsars, possibly suggesting a different origin. Future papers will use these data to constrain or detect the signatures of gravitational-wave signals., Published in the Astrophysical Journal Supplement Series

Published
2017

50. Statistical analyses for NANOGrav 5-year timing residuals

Author

Fredrick A. Jenet, Yan Wang, X. Siemens, James M. Cordes, Dustin R. Madison, Shami Chatterjee, Paul Demorest, Michele Vallisneri, Timothy Dolch, Michael T. Lam, Joanna M. Rankin, Justin A. Ellis, Maura McLaughlin, Delphine Perrodin, ITA, USA, and CHN

Subjects
010308 nuclear & particles physics, Gravitational wave, FOS: Physical sciences, Astronomy and Astrophysics, White noise, Geodesy, 01 natural sciences, Noise, Pulsar, Space and Planetary Science, Observatory, 0103 physical sciences, Outlier, Arecibo Observatory, Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Mathematics, Statistical hypothesis testing
Abstract

In pulsar timing, timing residuals are the differences between the observed times of arrival and the predictions from the timing model. A comprehensive timing model will produce featureless residuals, which are presumably composed of dominating noise and weak physical effects excluded from the timing model (e.g. gravitational waves). In order to apply the optimal statistical methods for detecting the weak gravitational wave signals, we need to know the statistical properties of the noise components in the residuals. In this paper we utilize a variety of non-parametric statistical tests to analyze the whiteness and Gaussianity of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 5-year timing data which are obtained from the Arecibo Observatory and the Green Bank Telescope from 2005 to 2010 (Demorest et al. 2013). We find that most of the data are consistent with white noise; Many data deviate from Gaussianity at different levels, nevertheless, removing outliers in some pulsars will mitigate the deviations., Comment: 15 pages, 11 figures, 2 tables. Accepted by RAA

Published
2017

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