994 results on '"Smith Krista"'
Search Results
2. Revisiting radio variability of the blazar 3C 454.3
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Tripathi, Ashutosh, Gupta, Alok C., Smith, Krista Lynne, Wiita, Paul J., Aller, Margo F., Volvach, Alexandr E., Lähteenmäki, Anne, Aller, Hugh D., Tornikoski, Merja, and Volvach, Larisa N.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We examine lengthy radio light curves of the flat spectrum radio galaxy 3C 454.3 for possible quasi-periodic oscillations (QPOs). The data used in this work were collected at five radio frequencies, 4.8, 8.0, 14.5, 22.0, and 37.0 GHz between 1979--2013 as observed at the University of Michigan Radio Astronomical Observatory, Crimean Astrophysical Observatory, and Aalto University Mets{\"a}hovi Radio Observatory. We employ generalized Lomb-Scargle periodogram and weighted wavelet transform analyses to search for periodicities in these light curves. We confirm a QPO period of $\sim$ 2000 day to be at least 4$\sigma$ significant using both methods at all five radio frequencies between 1979 and 2007, after which a strong flare changed the character of the light curve. We also find a $\sim$~600 day period which is at least 4$\sigma$ significant, but only in the 22.0 and 37.0 GHz light curves. We briefly discuss physical mechanisms capable of producing such variations., Comment: 19 pages, 11 figures, Published in the Astrophysical Journal
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- 2024
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3. MoonLITE: a CLPS-delivered NASA Astrophysics Pioneers lunar optical interferometer for sensitive, milliarcsecond observing
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van Belle, Gerard T., Ciardi, David, Hillsberry, Daniel, Jorgensen, Anders, Monnier, John, Smith, Krista Lynne, Boyajian, Tabetha, Carpenter, Kenneth, Clark, Catherine, Rau, Gioia, and Schaefer, Gail
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
MoonLITE (Lunar InTerferometry Explorer) is an Astrophysics Pioneers proposal to develop, build, fly, and operate the first separated-aperture optical interferometer in space, delivering sub-mas science results. MoonLITE will leverage the Pioneers opportunity for utilizing NASA's Commercial Lunar Payload Services (CLPS) to deliver an optical interferometer to the lunar surface, enabling unprecedented discovery power by combining high spatial resolution from optical interferometry with deep sensitivity from the stability of the lunar surface. Following landing, the CLPS-provided rover will deploy the pre-loaded MoonLITE outboard optical telescope 100 meters from the lander's inboard telescope, establishing a two-element interferometric observatory with a single deployment. MoonLITE will observe targets as faint as 17th magnitude in the visible, exceeding ground-based interferometric sensitivity by many magnitudes, and surpassing space-based optical systems resolution by a factor of 50 times. The capabilities of MoonLITE open a unique discovery space that includes direct size measurements of the smallest, coolest stars and substellar brown dwarfs; searches for close-in stellar companions orbiting exoplanet-hosting stars that could confound our understanding and characterization of the frequency of Earth-like planets; direct size measurements of young stellar objects and characterization of the terrestrial planet-forming regions of these young stars; measurements of the inner regions and binary fraction of active galactic nuclei; and a probe of the very nature of spacetime foam itself. A portion of the observing time will also be made available to the broader community via a guest observer program. MoonLITE takes advantage of the CLPS opportunity and delivers an unprecedented combination of sensitivity and angular resolution at the remarkably affordable cost point of Pioneers., Comment: 13 pages, 8 figures, SPIE Astronomical Telescopes + Instrumentation 2024
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- 2024
4. SU(3) Gauge Symmetry: An Experimental Review of Diffractive Physics in e+p, p+p, p+A, and A+A Collision Systems
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Smith, Krista L.
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Nuclear Experiment ,High Energy Physics - Phenomenology - Abstract
This review focuses on diffractive physics, which involves the long-range interactions of the strong nuclear force at high energies described by SU(3) gauge symmetry. It is expected that diffractive processes account for nearly 40% of the total cross-section at LHC energies. These processes consist of soft-scale physics where perturbation theory cannot be applied. Although highly successful and often described as a perfect theory, quantum chromodynamics relies heavily on perturbation theory, a model best suited for hard-scale physics. The study of pomerons could help bridge the soft and hard processes and provide a complete description of the theory of the strong interaction across the full momentum spectrum. Here, we will discuss some of the features of diffractive physics, experimental results from SPS, HERA, and the LHC, and where the field could potentially lead. With the recent publication of the odderon discovery in 2021 by the D0 and TOTEM collaborations and the new horizon of physics that lies ahead with the upcoming Electron-Ion Collider at Brookhaven National Laboratory, interest is seemingly piquing in high energy diffractive physics.
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- 2024
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5. Rapid multi-band space-based optical timing: revolutionizing accretion physics
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Smith, Krista Lynne
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Optical timing with rapid, seconds-to-minutes cadences with high photometric precision and gap-free long baselines is necessary for an unambiguous physical picture of accretion phenomena, and is only possible from space. Exoplanet-hunting missions like Kepler and TESS have offered an outstanding new window into detailed jet and accretion physics, but have been severely hampered by incomplete calibration and systematics treatments and, most especially, a monochromatic single wide bandpass. Advances made using Kepler and TESS survey data, when considered alongside detailed, expensive multi-color experiments done from the ground, reveal the enormous potential of a space-based multi-color optical timing mission with a high energy focus., Comment: 5 pages, no figures. Published in Frontiers in Astronomy and Space Sciences
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- 2024
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6. Optical Variability Properties of Southern TESS Blazars
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Dingler, Ryne and Smith, Krista Lynne
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - Abstract
We present a study of high-cadence, high-precision, optical light curves from the TESS satellite of 67 blazars in the southern sky. We provide descriptive flux statistics, power spectral density model parameters, and characteristic variability timescales. We find that only 15 BL Lacertae objects (BLLs) and 18 Flat Spectrum Radio Quasars (FSRQs) from the initial 26 and 41, respectively exhibit statistically-significant variability. We employ an adapted Power Spectral Response method to test the goodness of fit for the power spectral density function (PSD) to 3 power-law variant models. From our best-fitting description of the PSD, we extract the high-frequency power-spectral slopes and, if present, determine the significant bend or break in the model to identify characteristic timescales. We find no significant difference in the excess variance or rms-scatter between blazar subpopulations. We identify a linear rms-flux relation in ~69% of our sample, in which ~20% show a strong correlation. We find that both subpopulations of blazars show power spectral slope of $\alpha$~2 in which a broken power-law best fits 5 BLL & 6 FSRQ and a bending power-law best fits 1 BLL & 5 FSRQ. The shortest timescales of variability in each light curve range widely from minutes to weeks. Additionally, the objects' characteristic timescales range from ~0.8-8 days, consistent with the optical variability originating in the jet.
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- 2024
7. Search for Quasi-Periodic Oscillations in TESS light curves of bright Fermi Blazars
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Tripathi, Ashutosh, Smith, Krista Lynne, Wiita, Paul J., and Wagoner, Robert V.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
In a previous paper, we reported evidence for quasi-periodicities in the \textsl{TESS} light curves of BL Lacerate and two other blazars found serendipitously in the SDSS AGN catalog. In this work, we find tentative evidence for quasi-periodic features in the \textsl{TESS} observations of five sources in the fourth catalog of the Fermi--LAT (4FGL) sources: J090453.4$-$573503, J2345$-$1555, B0422+004, J002159.2$-$514028, and B0537$-$441. We analysed the \textsl{TESS} light curves of these blazars that we extracted using a customized approach. The quasi-periodic oscillations (QPOs) are searched for using two timing analysis techniques: generalized Lomb-Scargle periodogram and weighted wavelet Z-transform. Their apparent periods lie in the range of 2.8--6.5 days and have at least 3$\sigma$ significance in both of these methods. QPOs at such timescales can originate from the kink instability model which relates the quasi-periodic feature with the growth of kinks in the magnetized relativistic jets. We performed MCMC simulations to obtain the posterior distribution of parameters associated with this model and found the kink period consistent with previous studies., Comment: 12 pages, 4 figures. Accepted for publication in MNRAS main journal
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- 2024
8. Optical Quasi-periodic Oscillations in the TESS light curves of three blazars
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Tripathi, Ashutosh, Smith, Krista Lynne, Wiita, Paul J., and Wagoner, Robert V.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the time series analysis of TESS light curves of three blazars, BL Lacertae, 1RXS J111741.0+254858, and 1RXS J004519.6+212735, obtained using a customized approach for extracting AGN light curves. We find tentative evidence for quasi-periodic oscillations (QPOs) in these light curves that range from 2 to 6 days. Two methods of analysis are used for assessing their significance: generalized Lomb-Scargle periodograms and weighted wavelet Z-transforms. The different approaches of these methods together ensure a robust measurement of the significance of the claimed periodicities. We can attribute the apparent QPOs to the kink instability model which postulates that the observed QPOs are related to the temporal growth of kinks in the magnetized relativistic jet. We confirm the application of this model to BL Lacertae and extend the kink instability model to the other two BL Lac objects., Comment: Accepted for publication in MNRAS
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- 2023
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9. The Rapid Optical Variability of the Nearby Radio-Loud AGN Pictor A: Introducing the Quaver Pipeline for AGN Science with TESS
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Smith, Krista Lynne and Sartori, Lia
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
The sampling strategy of the Transiting Exoplanet Survey Satellite (TESS) make TESS light curves extremely valuable to investigate high cadence optical variability of AGN. However, because the TESS instrument was primarily designed for exoplanet science, the use of the satellite for other applications requires careful treatment of the data. In this paper we introduce Quaver, a new software tool designed specifically to extract TESS light curves of extended and faint sources presenting stochastic variability. We then use this new tool to extract light curves of the nearby radio-loud AGN Pictor A, and perform a temporal and power spectral analysis of its high cadence optical variability. The obtained light curves are well fit with a damped random walk (DRW) model, exhibiting both stochastic AGN variations and flaring behavior. The DRW characteristic timescales $\tau_{\rm DRW} \sim 3-6$ days during more quiet periods, and $\tau_{\rm DRW} \sim 0.8$ days for periods with strong flares, even when the flares themselves are masked from the DRW fit. The observed timescales are consistent with the dynamical, orbital and thermal timescales expected for the low black hole mass of Pictor A., Comment: 28 pages, 24 figures, 1 table. Accepted for publication in the Astrophysical Journal
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- 2023
10. A Phenomenon Resembling Early Superhumps in a New SU UMa-Type Dwarf Nova with a 2-Hour Orbital Period
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Boyle, Rebecca, Littlefield, Colin, Garnavich, Peter, Ridden-Harper, Ryan, Szkody, Paula, Boyd, Patricia, and Smith, Krista Lynne
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We investigate K2BS5, an optical transient that we identified in Campaign 13 of the Kepler/K2 archives by the "K2 Background Survey", and classify it as a new SU UMa-type dwarf nova. Using the light curve generated from Kepler's long-cadence observation mode, we analyze the dwarf nova during quiescence and superoutburst. Following 20 days of quiescence at the start of the observation, the system entered a superoutburst lasting 12 days, after which it experienced at least one rebrightening. K2BS5 clearly meets the criteria for an SU UMa star, but at the peak of the superoutburst, it also shows double-wave oscillations consistent with the spectroscopic orbital period, a phenomenon that closely resembles early superhumps in WZ Sge stars. While we do not classify K2BS5 as a WZ Sge system, we discuss how this phenomenon could complicate efforts to use the suspected detection of early superhumps to distinguish SU UMa-type dwarf novae from the recently recognized class of long-orbital-period WZ Sge systems., Comment: 11 pages, 7 figures. Accepted for publication in the Astronomical Journal
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- 2023
11. BASS XXXIV: A Catalog of the Nuclear Mm-wave Continuum Emission Properties of AGNs Constrained on Scales $\lesssim$ 100--200 pc
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Kawamuro, Taiki, Ricci, Claudio, Mushotzky, Richard F., Imanishi, Masatoshi, Bauer, Franz E., Ricci, Federica, Koss, Michael J., Privon, George C., Trakhtenbrot, Benny, Izumi, Takuma, Ichikawa, Kohei, Rojas, Alejandra F., Smith, Krista Lynne, Shimizu, Taro, Oh, Kyuseok, Brok, Jakob S. den, Baba, Shunsuke, Balokovic, Mislav, Chang, Chin-Shin, Kakkad, Darshan, Pfeifle, Ryan W., Temple, Matthew J., Ueda, Yoshihiro, Harrison, Fiona, Powell, Meredith C., Stern, Daniel, Urry, Meg, and Sanders, David B.
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Astrophysics - Astrophysics of Galaxies - Abstract
We present a catalog of the millimeter-wave (mm-wave) continuum properties of 98 nearby ($z <$ 0.05) active galactic nuclei (AGNs) selected from the 70-month Swift/BAT hard X-ray catalog that have precisely determined X-ray spectral properties and subarcsec-resolution ALMA Band-6 (211--275 GHz) observations as of 2021 April. Due to the hard-X-ray ($>$ 10 keV) selection, the sample is nearly unbiased for obscured systems at least up to Compton-thick-level obscuration, and provides the largest number of AGNs with high physical resolution mm-wave data ($\lesssim$ 100--200 pc). Our catalog reports emission peak coordinates, spectral indices, and peak fluxes and luminosities at 1.3 mm (230 GHz). Additionally, high-resolution mm-wave images are provided. Using the images and creating radial surface brightness profiles of mm-wave emission, we identify emission extending from the central source and isolated blob-like emission. Flags indicating the presence of these emission features are tabulated. Among 90 AGNs with significant detections of nuclear emission, 37 AGNs ($\approx$ 41%) appear to have both or one of extended or blob-like components. We, in particular, investigate AGNs that show well-resolved mm-wave components and find that these seem to have a variety of origins (i.e., a jet, radio lobes, a secondary AGN, stellar clusters, a narrow line region, galaxy disk, active star-formation regions, and AGN-driven outflows), and some components have currently unclear origins., Comment: 49 pages, 7 figures, 3 tables, accepted for publication in ApJS
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- 2023
12. The Nature of the IMBH Candidate CXO~J133815.6+043255: High-Frequency Radio Emission
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Smith, Krista Lynne, Magno, Macon, and Tripathi, Ashutosh
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - Abstract
The ultra-luminous X-ray source CXO~J133815.6+043255 is a strong candidate for a bona-fide intermediate mass black hole, residing in the outskirts of NGC~5252. We present 22~GHz radio observations of this source obtained serendipitously in an ongoing high-frequency imaging survey of radio-quiet Active Galactic Nuclei (AGN), and use this new data point to construct the broad-band radio spectral energy distribution (SED). We find that the SED exhibits a spectral slope of $\alpha=-0.66\pm0.02$, consistent with a steep spectrum from optically-thin synchrotron emission from an unresolved jet. We also find that the $L_R / L_X$ ratio is approximately $10^{-3}$, inconsistent with radio-quiet AGN and many ULXs but consistent with low-luminosity AGN (LLAGN) and radio-loud quasars. Together, these observations support the conclusion that CXO~J133815.6+043255 is an intermediate-mass black hole producing a low-mass analog of radio jets seen in classical quasars., Comment: 8 pages, 3 figures, accepted for publication in the Astrophysical Journal
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- 2023
13. BASS XXXV. The $M_\rm{BH}$-$\sigma_\rm{\star}$ Relation of 105-Month Swift-BAT Type 1 AGNs
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Caglar, Turgay, Koss, Michael J., Burtscher, Leonard, Trakhtenbrot, Benny, Erdim, M. Kiyami, Mejía-Restrepo, Julian E., Ricci, Federica, Powell, Meredith C., Ricci, Claudio, Mushotzky, Richard, Bauer, Franz E., Ananna, Tonima T., Bär, Rudolf E., Brandl, Bernhard, Brinchmann, Jarle, Harrison, Fiona, Ichikawa, Kohei, Kakkad, Darshan, Oh, Kyuseok, Riffel, Rogério, Sartori, Lia F., Smith, Krista L., Stern, Daniel, and Urry, C. Megan
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Astrophysics - Astrophysics of Galaxies - Abstract
We present two independent measurements of stellar velocity dispersions ( $\sigma_\rm{\star}$ ) from the Ca\,H+K \& Mg\,\textsc{i} region (3880--5550~\AA) and the Calcium Triplet region (CaT, 8350--8750~\AA) for 173 hard X-ray-selected Type 1 AGNs ($z \leq$ 0.08) from the 105-month Swift-BAT catalog. We construct one of the largest samples of local Type 1 AGNs that have both single-epoch (SE) 'virial' black hole mass ($M_\rm{BH}$) estimates and $\sigma_\rm{\star}$ measurements obtained from high spectral resolution data, allowing us to test the usage of such methods for SMBH studies. We find that the two independent $\sigma_\rm{\star}$ measurements are highly consistent with each other, with an average offset of only $0.002\pm0.001$ dex. Comparing $M_\rm{BH}$ estimates based on broad emission lines and stellar velocity dispersion measurements, we find that the former is systematically lower by $\approx$0.12 dex. Consequently, Eddington ratios estimated through broad-line $M_\rm{BH}$ determinations are similarly biased (but in the opposite way). We argue that the discrepancy is driven by extinction in the broad-line region (BLR). We also find an anti-correlation between the offset from the $M_\rm{BH}$ - $\sigma_\rm{\star}$ relation and the Eddington ratio. Our sample of Type 1 AGNs shows a shallower $M_\rm{BH}$ - $\sigma_\rm{\star}$ relation (with a power law exponent of $\approx$3.5) compared with that of inactive galaxies (with a power-law exponent of $\approx$4.5), confirming earlier results obtained from smaller samples., Comment: Accepted by the ApJ
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- 2023
14. A Tight Correlation Between Millimeter and X-ray Emission in Accreting Massive Black Holes from <100 Milliarcsecond-resolution ALMA Observations
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Ricci, Claudio, Chang, Chin-Shin, Kawamuro, Taiki, Privon, George, Mushotzky, Richard, Trakhtenbrot, Benny, Laor, Ari, Koss, Michael J., Smith, Krista L., Gupta, Kriti K., Dimopoulos, Georgios, Aalto, Susanne, and Ros, Eduardo
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - Abstract
Recent studies have proposed that the nuclear millimeter continuum emission observed in nearby active galactic nuclei (AGN) could be created by the same population of electrons that gives rise to the X-ray emission that is ubiquitously observed in accreting black holes. We present the results of a dedicated high spatial resolution ($\sim$60-100 milliarcsecond) ALMA campaign on a volume-limited ($<50$ Mpc) sample of 26 hard X-ray ($>10$ keV) selected radio-quiet AGN. We find an extremely high detection rate (25/26 or $94^{+3}_{-6}\%$), which shows that nuclear emission at mm-wavelengths is nearly ubiquitous in accreting SMBHs. Our high-resolution observations show a tight correlation between the nuclear (1-23 pc) 100GHz and the intrinsic X-ray emission (1$\sigma$ scatter of $0.22$ dex). The ratio between the 100GHz continuum and the X-ray emission does not show any correlation with column density, black hole mass, Eddington ratio or star formation rate, which suggests that the 100GHz emission can be used as a proxy of SMBH accretion over a very broad range of these parameters. The strong correlation between 100GHz and X-ray emission in radio-quiet AGN could be used to estimate the column density based on the ratio between the observed 2-10keV ($F^{\rm obs}_{2-10\rm\,keV}$) and 100GHz ($F_{100\rm\,GHz}$) fluxes. Specifically, a ratio $\log (F^{\rm obs}_{2-10\rm\,keV}/F_{100\rm\,GHz})\leq 3.5$ strongly suggests that a source is heavily obscured [$\log (N_{\rm H}/\rm cm^{-2})\gtrsim 23.8$]. Our work shows the potential of ALMA continuum observations to detect heavily obscured AGN (up to an optical depth of one at 100GHz, i.e. $N_{\rm H}\simeq 10^{27}\rm\,cm^{-2}$), and to identify binary SMBHs with separations $<100$ pc, which cannot be probed by current X-ray facilities., Comment: ApJL in press
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- 2023
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15. UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation
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Koss, Michael J., Treister, Ezequiel, Kakkad, Darshan, Casey-Clyde, J. Andrew, Kawamuro, Taiki, Williams, Jonathan, Foord, Adi, Trakhtenbrot, Benny, Bauer, Franz E., Privon, George C., Ricci, Claudio, Mushotzky, Richard, Barcos-Munoz, Loreto, Blecha, Laura, Connor, Thomas, Harrison, Fiona, Liu, Tingting, Magno, Macon, Mingarelli, Chiara M. F., Muller-Sanchez, Francisco, Oh, Kyuseok, Shimizu, T. Taro, Smith, Krista L., Stern, Daniel, Tello, Miguel Parra, and Urry, C. Megan
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present multi-wavelength high-spatial resolution (~0.1'', 70 pc) observations of UGC 4211 at z=0.03474, a late-stage major galaxy merger at the closest nuclear separation yet found in near-IR imaging (0.32'', ~230 pc projected separation). Using Hubble Space Telescope/STIS, VLT/MUSE+AO, Keck/OSIRIS+AO spectroscopy, and ALMA observations, we show that the spatial distribution, optical and NIR emission lines, and millimeter continuum emission are all consistent with both nuclei being powered by accreting supermassive black holes (SMBHs). Our data, combined with common black hole mass prescriptions, suggests that both SMBHs have similar masses, log MBH~8.1 (south) and log MBH~8.3 (north), respectively. The projected separation of 230 pc (~6X the black hole sphere of influence) represents the closest-separation dual AGN studied to date with multi-wavelength resolved spectroscopy and shows the potential of nuclear (<50 pc) continuum observations with ALMA to discover hidden growing SMBH pairs. While the exact occurrence rate of close-separation dual AGN is not yet known, it may be surprisingly high, given that UGC 4211 was found within a small, volume-limited sample of nearby hard X-ray detected AGN. Observations of dual SMBH binaries in the sub-kpc regime at the final stages of dynamical friction provide important constraints for future gravitational wave observatories., Comment: 19 pages, 7 figures, 2 tables, published in ApJL
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- 2023
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16. J/$\psi$ and $\psi$(2S) Production in Small Systems with PHENIX
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Smith, Krista
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Nuclear Experiment - Abstract
The suppression of the $\psi$(2S) nuclear modification factor has been seen as a trademark signature of final state effects in large collision systems for decades. In small systems, deviations of the nuclear modification from unity had been attributed to cold nuclear matter effects until the observation of strong differential suppression of the $\psi$(2S) state in $p/d+$A collisions, which suggests the presence of final state effects. In this paper, we present results of J/$\psi$ and $\psi$(2S) measurements in the dimuon decay channel for $p+p$, $p+$Al, and $p+$Au collision systems at $\sqrt{s_{_{NN}}}$ = 200 GeV. Key results include the nuclear modification factors $R_{pA}$ as a function of centrality and rapidity. The measurements are compared with shadowing and transport model predictions, as well as to complementary measurements at LHC energies.
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- 2022
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17. BASS XXXII: Studying the Nuclear Mm-wave Continuum Emission of AGNs with ALMA at Scales $\lesssim$ 100-200 pc
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Kawamuro, Taiki, Ricci, Claudio, Imanishi, Masatoshi, Mushotzky, Richard F., Izumi, Takuma, Ricci, Federica, Bauer, Franz E., Koss, Michael J., Trakhtenbrot, Benny, Ichikawa, Kohei, Rojas, Alejandra F., Smith, Krista Lynne, Shimizu, Taro, Oh, Kyuseok, Brok, Jakob S. den, Baba, Shunsuke, Baloković, Mislav, Chang, Chin-Shin, Kakkad, Darshan, Pfeifle, Ryan W., Privon, George C., Temple, Matthew J., Ueda, Yoshihiro, Harrison, Fiona, Powell, Meredith C., Stern, Daniel, Urry, Meg, and Sanders, David B.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
To understand the origin of nuclear ($\lesssim$ 100 pc) millimeter-wave (mm-wave) continuum emission in active galactic nuclei (AGNs), we systematically analyzed sub-arcsec resolution Band-6 (211-275 GHz) ALMA data of 98 nearby AGNs ($z <$ 0.05) from the 70-month Swift/BAT catalog. The sample, almost unbiased for obscured systems, provides the largest number of AGNs to date with high mm-wave spatial resolution sampling ($\sim$ 1-200 pc), and spans broad ranges of 14-150 keV luminosity {$40 < \log[L_{\rm 14-150}/({\rm erg\,s^{-1}})] < 45$}, black hole mass [$5 < \log(M_{\rm BH}/M_\odot) < 10$], and Eddington ratio ($-4 < \log \lambda_{\rm Edd} < 2$). We find a significant correlation between 1.3 mm (230 GHz) and 14-150 keV luminosities. Its scatter is $\approx$ 0.36 dex, and the mm-wave emission may serve as a good proxy of the AGN luminosity, free of dust extinction up to $N_{\rm H} \sim 10^{26}$ cm$^{-2}$. While the mm-wave emission could be self-absorbed synchrotron radiation around the X-ray corona according to past works, we also discuss different possible origins of the mm-wave emission; AGN-related dust emission, outflow-driven shocks, and a small-scale ($<$ 200 pc) jet. The dust emission is unlikely to be dominant, as the mm-wave slope is generally flatter than expected. Also, due to no increase in the mm-wave luminosity with the Eddington ratio, a radiation-driven outflow model is possibly not the common mechanism. Furthermore, we find independence of the mm-wave luminosity on indicators of the inclination angle from the polar axis of the nuclear structure, which is inconsistent with a jet model whose luminosity depends only on the angle., Comment: 44 pages, 35 figures, 3 tables, accepted for publication in ApJ; modified format, added supplementary figure (Fig. 32)
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- 2022
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18. BAT AGN Spectroscopic Survey XXI: The Data Release 2 Overview
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Koss, Michael J., Trakhtenbrot, Benny, Ricci, Claudio, Bauer, Franz E., Treister, Ezequiel, Mushotzky, Richard, Urry, C. Megan, Ananna, Tonima T., Balokovic, Mislav, Brok, Jakob S. den, Cenko, S. Bradley, Harrison, Fiona, Ichikawa, Kohei, Lamperti, Isabella, Lein, Amy, Mejia-Restrepo, Julian E., Oh, Kyuseok, Pacucci, Fabio, Pfeifle, Ryan W., Powell, Meredith C., Privon, George C., Ricci, Federica, Salvato, Mara, Schawinski, Kevin, Shimizu, Taro, Smith, Krista L., and Stern, Daniel
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
The BAT AGN Spectroscopic Survey (BASS) is designed to provide a highly complete census of the key physical parameters of supermassive black holes (SMBHs) that power local active galactic nuclei (AGN) (z<0.3), including their bolometric luminosity, black hole mass, accretion rates, and line-of-sight gas obscuration, and the distinctive properties of their host galaxies (e.g., star formation rates, masses, and gas fractions). We present an overview of the BASS data release 2 (DR2), an unprecedented spectroscopic survey in spectral range, resolution, and sensitivity, including 1449 optical (3200-10000 A) and 233 NIR (1-2.5 um) spectra for the brightest 858 ultra-hard X-ray (14-195 keV) selected AGN across the entire sky and essentially all levels of obscuration. This release provides a highly complete set of key measurements (emission line measurements and central velocity dispersions), with 99.9% measured redshifts and 98% black hole masses estimated (for unbeamed AGN outside the Galactic plane). The BASS DR2 AGN sample represents a unique census of nearby powerful AGN, spanning over 5 orders of magnitude in AGN bolometric luminosity, black hole mass, Eddington ratio, and obscuration. The public BASS DR2 sample and measurements can thus be used to answer fundamental questions about SMBH growth and its links to host galaxy evolution and feedback in the local universe, as well as open questions concerning SMBH physics. Here we provide a brief overview of the survey strategy, the key BASS DR2 measurements, data sets and catalogs, and scientific highlights from a series of DR2-based works., Comment: 21 pages, 6 figures, 5 tables, published in ApJS as part of BASS DR2 special issue
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- 2022
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19. Considering the “How” of SEL: A framework for the pedagogies of social and emotional learning
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Zieher, Almut K., Bailey, Craig S., Cipriano, Christina, McNaboe, Tessa, Smith, Krista, and Strambler, Michael J.
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- 2024
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20. 2MASX J00423991+3017515: An offset active galactic nucleus in an interacting system
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Hogg, J. Drew, Blecha, Laura, Reynolds, Christopher S., Smith, Krista Lynne, and Winter, Lisa M.
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Astrophysics - Astrophysics of Galaxies - Abstract
We present a spectroscopic and imaging study of an abnormal active galactic nucleus (AGN), 2MASX J00423991+3017515. This AGN is newly identified in the hard X-rays by the Swift BAT All-Sky survey and found in an edge-on disk galaxy interacting with a nearby companion. Here, we analyze the first optical spectra obtained for this system (taken in 2011 and 2016), high-resolution imaging taken with the Hubble Space Telescope and Chandra X-ray Observatory, and 1" imaging with the Very Large Array. Two unique properties are revealed: the peaks of the broad Balmer emission lines (associated with gas orbiting very near the supermassive black hole) are blue shifted from the corresponding narrow line emission and host galaxy absorption by 1540 km/s, and the AGN is spatially displaced from the apparent center of its host galaxy by 3.8 kpc. We explore several scenarios to explain these features, along with other anomalies, and propose that 2MASX J00423991+3017515 may be an AGN with an unusually strong wind residing in a uniquely configured major merger, or that it is an AGN recoiling from either a gravitational "slingshot" in a three-body interaction or from a kick due to the asymmetric emission of gravitational waves following the coalescence of two progenitor supermassive black holes., Comment: 17 pages, 10 figures, 4 tables, accepted for publication in MNRAS
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- 2021
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21. GRB 191016A: A Long Gamma-Ray Burst Detected by TESS
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Smith, Krista Lynne, Ridden-Harper, Ryan, Fausnaugh, Michael, Daylan, Tansu, Omodei, Nicola, Racusin, Judith, Weaver, Zachary, Barclay, Thomas, Veres, Péter, Kann, D. Alexander, and Arimoto, Makoto
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The TESS exoplanet-hunting mission detected the rising and decaying optical afterglow of GRB 191016A, a long Gamma-Ray Burst (GRB) detected by Swift-BAT but without prompt XRT or UVOT follow-up due to proximity to the moon. The afterglow has a late peak at least 1000 seconds after the BAT trigger, with a brightest-detected TESS datapoint at 2589.7 s post-trigger. The burst was not detected by Fermi-LAT, but was detected by Fermi-GBM without triggering, possibly due to the gradual nature of rising light curve. Using ground-based photometry, we estimate a photometric redshift of $z_\mathrm{phot} = 3.29\pm{0.40}$. Combined with the high-energy emission and optical peak time derived from TESS, estimates of the bulk Lorentz factor $\Gamma_\mathrm{BL}$ range from $90-133$. The burst is relatively bright, with a peak optical magnitude in ground-based follow-up of $R=15.1$ mag. Using published distributions of GRB afterglows and considering the TESS sensitivity and sampling, we estimate that TESS is likely to detect $\sim1$ GRB afterglow per year above its magnitude limit., Comment: 10 pages, 7 figures. Accepted for publication in the Astrophysical Journal
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- 2021
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22. Properties of a Previously Unidentified Instrumental Signature in $\textit{Kepler/K2}$ that was Confused for AGN Variability
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Moreno, Jackeline, Buttry, Rachel, O'Brien, John, Vogeley, Michael S., Richards, Gordon T., and Smith, Krista Lynne
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
The $\textit{Kepler}$ satellite potentially provides the highest precision photometry of active galactic nuclei (AGN) available to investigate short-timescale optical variability. We targeted quasars from the Sloan Digital Sky Survey that lie in the fields of view of the $\textit{Kepler/K2}$ campaigns. Based on those observations, we report the discovery and properties of a previously unidentified instrumental signature in K2. Systematic errors in K2, beyond those due to the motion of the detector, plague our AGN and other faint-target, guest-observer science proposals. Weakly illuminated pixels are dominated by low frequency trends that are both non-astrophysical and correlated from object to object. A critical clue to understanding this instrumental noise is that different targets observed in the same channels of Campaign 8 (rear facing) and Campaign 16 (forward facing) had nearly identical light curves after time reversal of one of the campaigns. This observation strongly suggests that the underlying problem relates to the relative Sun-spacecraft-field orientation, which was approximately the same on day 1 of Campaign 8 as the last day of Campaign 16. Furthermore, we measure that the instrumental signature lags in time as a function of radius from the center of the detector, crossing channel boundaries. Systematics documented in this investigation are unlikely to be due to Moir\'{e} noise, rolling band, or pointing jitter. Instead this work strongly suggests temperature-dependent focus changes that are further subject to channel variations. Further characterization of this signature is crucial for rehabilitating K2 data for use in investigations of AGN light curves., Comment: 21 pages, 16 figures
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- 2020
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23. Getting Ready for LISA: The Data, Support and Preparation Needed to Maximize US Participation in Space-Based Gravitational Wave Science
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Holley-Bockelmann, Kelly, Bellovary, Jillian, Bender, Peter, Berti, Emanuele, Brown, Warren, Caldwell, Robert, Cornish, Neil, Darling, Jeremy, Digman, Matthew, Eracleous, Mike, Gultekin, Kayhan, Haiman, Zoltan, Key, Joey, Larson, Shane, Liu, Xin, McWilliams, Sean, Natarajan, Priyamvada, Shoemaker, David, Shoemaker, Deirdre, Smith, Krista Lynne, Soares-Santos, Marcelle, and Stebbins, Robin
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,General Relativity and Quantum Cosmology - Abstract
The NASA LISA Study Team was tasked to study how NASA might support US scientists to participate and maximize the science return from the Laser Interferometer Space Antenna (LISA) mission. LISA is gravitational wave observatory led by ESA with NASA as a junior partner, and is scheduled to launch in 2034. Among our findings: LISA science productivity is greatly enhanced by a full-featured US science center and an open access data model. As other major missions have demonstrated, a science center acts as both a locus and an amplifier of research innovation, data analysis, user support, user training and user interaction. In its most basic function, a US Science Center could facilitate entry into LISA science by hosting a Data Processing Center and a portal for the US community to access LISA data products. However, an enhanced LISA Science Center could: support one of the parallel independent processing pipelines required for data product validation; stimulate the high level of research on data analysis that LISA demands; support users unfamiliar with a novel observatory; facilitate astrophysics and fundamental research; provide an interface into the subtleties of the instrument to validate extraordinary discoveries; train new users; and expand the research community through guest investigator, postdoc and student programs. Establishing a US LISA Science Center well before launch can have a beneficial impact on the participation of the broader astronomical community by providing training, hosting topical workshops, disseminating mock catalogs, software pipelines, and documentation. Past experience indicates that successful science centers are established several years before launch; this early adoption model may be especially relevant for a pioneering mission like LISA., Comment: 93 pages with a lovely cover page thanks to Bernard Kelly and Elizabeth Ferrara
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- 2020
24. Confrontation of Observation and Theory: High Frequency QPOs in X-ray Binaries, Tidal Disruption Events, and Active Galactic Nuclei
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Smith, Krista Lynne, Tandon, Celia R., and Wagoner, Robert V.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We compile observations of high-frequency quasi-periodic oscillations (QPOs) around black holes, both stellar and supermassive, and compare their positions in the parameter space of black hole mass, spin, and oscillation frequency. We find that supermassive black holes occupy a separate region of parameter space than stellar, and further, that QPOs seen around tidal disruption events rather than Seyfert-type AGN occupy an entirely different space. We then compare these results to the orbital resonance, diskoseismic, warped disk, and disk-jet coupling theoretical models for the origin of high-frequency QPOs. We find that while oscillations around stellar mass black holes are generally consistent with the above models, supermassive black holes are decidedly not. Oscillations seen in tidal disruption events are consistent with oscillations near the frequency of the innermost stable circular orbit (ISCO), while QPOs in AGN are not accounted for by any of the physical models in consideration. This indicates that despite the scale invariance of accretion processes implied by a decades-wide correlation between QPO frequency and black hole mass, any theory of high frequency QPOs must relate the frequency to more than just the mass and spin., Comment: 9 pages, 3 figures, 2 tables. Accepted for publication in the Astrophysical Journal
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- 2020
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25. Significant Suppression of Star Formation in Radio-Quiet AGN Host Galaxies with Kiloparsec-Scale Radio Structures
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Smith, Krista Lynne, Koss, Michael, Mushotzky, Richard, Wong, O. Ivy, Shimizu, T. Taro, Ricci, Claudio, and Ricci, Federica
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Astrophysics - Astrophysics of Galaxies - Abstract
We conducted 22~GHz 1" JVLA imaging of 100 radio-quiet X-ray selected AGN from the Swift-BAT survey. We find AGN-driven kiloparsec-scale radio structures inconsistent with pure star formation in 11 AGN. The host galaxies of these AGN lie significantly below the star-forming main sequence, indicating suppressed star formation. While these radio structures tend to be physically small compared to the host galaxy, the global star formation rate of the host is affected. We evaluate the energetics of the radio structures interpreted first as immature radio jets, and then as consequences of an AGN-driven radiative outflow, and compare them to two criteria for successful feedback: the ability to remove the CO-derived molecular gas mass from the galaxy gravitational potential and the kinetic energy transfer to molecular clouds leading to $v_\mathrm{cloud} > \sigma_*$. In most cases, the jet interpretation is insufficient to provide the energy necessary to cause the star formation suppression. Conversely, the wind interpretation provides ample energy in all but one case. We conclude that it is more likely that the observed suppression of star formation in the global host galaxy is due to ISM interactions of a radiative outflow, rather than a small-scale radio jet., Comment: 15 pages, 3 figures, 2 tables. Accepted for publication in the Astrophysical Journal
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- 2020
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26. BAT AGN Spectroscopic Survey -- XV: The High Frequency Radio Cores of Ultra-hard X-ray Selected AGN
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Smith, Krista Lynne, Mushotzky, Richard F., Koss, Michael, Trakhtenbrot, Benny, Ricci, Claudio, Wong, O. Ivy, Bauer, Franz E., Ricci, Federica, Vogel, Stuart, Stern, Daniel, Powell, Meredith C., Urry, C. Meg, Harrison, Fiona, Mejia-Restrepo, Julian, Oh, Kyuseok, Baek, Junhyun, and Chung, Aeree
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Astrophysics - Astrophysics of Galaxies - Abstract
We have conducted 22 GHz radio imaging at 1" resolution of 100 low-redshift AGN selected at 14-195 keV by the Swift-BAT. We find a radio core detection fraction of 96%, much higher than lower-frequency radio surveys. Of the 96 radio-detected AGN, 55 have compact morphologies, 30 have morphologies consistent with nuclear star formation, and 11 have sub-kpc to kpc-scale jets. We find that the total radio power does not distinguish between nuclear star formation and jets as the origin of the radio emission. For 87 objects, we use optical spectroscopy to test whether AGN physical parameters are distinct between radio morphological types. We find that X-ray luminosities tend to be higher if the 22 GHz morphology is jet-like, but find no significant difference in other physical parameters. We find that the relationship between the X-ray and core radio luminosities is consistent with the $L_R/L_X \sim 10^{-5}$ of coronally active stars. We further find that the canonical fundamental planes of black hole activity systematically over-predict our radio luminosities, particularly for objects with star formation morphologies., Comment: 22 pages, 10 figures, 2 tables. Accepted for publication in MNRAS
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- 2020
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27. The BAT AGN Spectroscopic Survey -- XVIII. Searching for Supermassive Black Hole Binaries in the X-rays
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Liu, Tingting, Koss, Michael, Blecha, Laura, Ricci, Claudio, Trakhtenbrot, Benny, Mushotzky, Richard, Harrison, Fiona, Ichikawa, Kohei, Kakkad, Darshan, Oh, Kyuseok, Powell, Meredith, Privon, George C., Schawinski, Kevin, Shimizu, T. Taro, Smith, Krista Lynne, Stern, Daniel, Treister, Ezequiel, and Urry, C. Megan
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Theory predicts that a supermassive black hole binary (SMBHB) could be observed as a luminous active galactic nucleus (AGN) that periodically varies on the order of its orbital timescale. In X-rays, periodic variations could be caused by mechanisms including relativistic Doppler boosting and shocks. Here we present the first systematic search for periodic AGNs using $941$ hard X-ray light curves (14-195 keV) from the first 105 months of the Swift Burst Alert Telescope (BAT) survey (2004-2013). We do not find evidence for periodic AGNs in Swift-BAT, including the previously reported SMBHB candidate MCG+11$-$11$-$032. We find that the null detection is consistent with the combination of the upper-limit binary population in AGNs in our adopted model, their expected periodic variability amplitudes, and the BAT survey characteristics. We have also investigated the detectability of SMBHBs against normal AGN X-ray variability in the context of the eROSITA survey. Under our assumptions of a binary population and the periodic signals they produce which have long periods of hundreds of days, up to $13$% true periodic binaries can be robustly distinguished from normal variable AGNs with the ideal uniform sampling. However, we demonstrate that realistic eROSITA sampling is likely to be insensitive to long-period binaries because longer observing gaps reduce their detectability. In contrast, large observing gaps do not diminish the prospect of detecting binaries of short, few-day periods, as 19% can be successfully recovered, the vast majority of which can be identified by the first half of the survey., Comment: 17 pages, including 8 figures and 4 tables. Accepted for publication in ApJ
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- 2019
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28. A Dissection of Spatially Resolved AGN Feedback across the Electromagnetic Spectrum
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Fischer, Travis, Smith, Krista Lynne, Kraemer, Steve, Schmitt, Henrique, Crenshaw, D. Michael, Koss, Michael, Mushotzky, Richard, Larson, Kirsten, U, Vivian, and Rigby, Jane
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Astrophysics - Astrophysics of Galaxies - Abstract
We present optical SuperNova Integral Field Spectrograph (SNIFS) integral field spectroscopy, Hubble Space Telescope optical imaging, Chandra X-ray imaging, and Very Large Array radio interferometry of the merging galaxy 2MASX J04234080+0408017, which hosts a Seyfert 2 active galactic nucleus (AGN) at z = 0.046. Our observations reveal that radiatively driven, ionized gas outflows are successful to distances > 10 kpc due to the low mass of the host system, encompassing the entirety of the observed optical emission. We also find that at large radii, where observed velocities cannot be reproduced by radiative driving models, high velocity kinematics are likely due to mechanical driving from AGN winds impacting high density host material. This impacting deposits sufficient energy to shock the host material, producing thermal X-ray emission and cosmic rays, which in turn promote the formation of in situ radio structure in a pseudo-jet morphology along the high density lanes., Comment: Accepted for publication in ApJ. 20 pages, 20 figures
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- 2019
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29. Spikey: Self-Lensing Flares from Eccentric SMBH Binaries
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Hu, Betty X., D'Orazio, Daniel J., Haiman, Zoltan, Smith, Krista Lynne, Snios, Bradford, Charisi, Maria, and Di Stefano, Rosanne
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We examine the light curves of two quasars, motivated by recent suggestions that a supermassive black hole binary (SMBHB) can exhibit sharp lensing spikes. We model the variability of each light curve as due to a combination of two relativistic effects: the orbital relativistic Doppler boost and gravitational binary self-lensing. In order to model each system we extend previous Doppler plus self-lensing models to include eccentricity. The first quasar is identified in optical data as a binary candidate with a 20-yr period (Ark 120), and shows a prominent spike. For this source, we rule out the lensing hypothesis and disfavor the Doppler-boost hypothesis due to discrepancies in the measured vs. recovered values of the binary mass and optical spectral slope. The second source, which we nickname Spikey, is the rare case of an active galactic nucleus (AGN) identified in Kepler's high-quality, high-cadence photometric data. For this source, we find a model, consisting of a combination of a Doppler modulation and a narrow symmetric lensing spike, consistent with an eccentric SMBHB with a total mass of approximately 30 million solar masses, rest-frame orbital period T=418 days, eccentricity e=0.5, and seen at an inclination of 8 degrees from edge-on. This interpretation can be tested by monitoring Spikey for periodic behavior and recurring flares in the next few years. In preparation for such monitoring we present the first X-ray observations of this object taken by the Neil Gehrels Swift observatory., Comment: Accepted to MNRAS
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- 2019
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30. BAT AGN Spectroscopic Survey -- XIII. The nature of the most luminous obscured AGN in the low-redshift universe
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Bär, Rudolf E., Trakhtenbrot, Benny, Oh, Kyuseok, Koss, Michael J., Wong, O. Ivy, Ricci, Claudio, Schawinski, Kevin, Weigel, Anna K., Sartori, Lia F., Ichikawa, Kohei, Secrest, Nathan J., Stern, Daniel, Pacucci, Fabio, Mushotzky, Richard, Powell, Meredith C., Ricci, Federica, Sani, Eleonora, Smith, Krista L., Harrison, Fiona A., Lamperti, Isabella, and Urry, C. Megan
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present a multi wavelength analysis of 28 of the most luminous low-redshift narrow-line, ultra-hard X-ray selected active galactic nuclei (AGN) drawn from the 70 month Swift/BAT all-sky survey, with bolometric luminosities of log(L_bol/erg/s) > 45.25. The broad goal of our study is to determine whether these objects have any distinctive properties, potentially setting them aside from lower-luminosity obscured AGN in the local Universe. Our analysis relies on the first data release of the BAT AGN Spectroscopic Survey (BASS/DR1) and on dedicated observations with the VLT, Palomar, and Keck observatories. We find that the vast majority of our sources agree with commonly used AGN selection criteria which are based on emission line ratios and on mid-infrared colours. Our AGN are predominantly hosted in massive galaxies (9.8 < log(M_*/M_sun) < 11.7); based on visual inspection of archival optical images, they appear to be mostly ellipticals. Otherwise, they do not have distinctive properties. Their radio luminosities, determined from publicly available survey data, show a large spread of almost 4 orders of magnitude - much broader than what is found for lower X-ray luminosity obscured AGN in BASS. Moreover, our sample shows no preferred combination of black hole masses (M_BH) and/or Eddington ratio (lambda_Edd), covering 7.5 < log(M_BH/M_sun) < 10.3 and 0.01 < lambda_Edd < 1. Based on the distribution of our sources in the lambda_Edd-N_H plane, we conclude that our sample is consistent with a scenario where the amount of obscuring material along the line of sight is determined by radiation pressure exerted by the AGN on the dusty circumnuclear gas., Comment: Accepted for publication in MNRAS (ID: stz2309)
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- 2019
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31. BAT AGN Spectroscopic Survey -- XVII: The Parsec-scale Jet Properties of the Ultra Hard X-ray Selected Local AGN
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Baek, Junhyun, Chung, Aeree, Schawinski, Kevin, Oh, Kyuseok, Wong, O. Ivy, Koss, Michael, Ricci, Claudio, Trakhtenbrot, Benny, Smith, Krista Lynne, and Ueda, Yoshihiro
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
We have performed a very long baseline interferometry (VLBI) survey of local (z < 0.05) ultra hard X-ray (14-195 keV) selected active galactic nuclei (AGN) from the Swift Burst Alert Telescope (BAT) using KVN, KaVA, and VLBA. We first executed fringe surveys of 142 BAT-detected AGN at 15 or 22 GHz. Based on the fringe surveys and archival data, we find 10/279 nearby AGN (~4%) VLBI have 22 GHz flux above 30 mJy. This implies that the X-ray AGN with a bright nuclear jet are not common. Among these 10 radio-bright AGN, we obtained 22 GHz VLBI imaging data of our own for four targets and reprocessed archival data for six targets. We find that, although our 10 AGN observed with VLBI span a wide range of pc-scale morphological types, they lie on a tight linear relation between accretion luminosity and nuclear jet luminosity. Our result suggests that a powerful nuclear radio jet correlates with the accretion disc luminosity. We also probed the fundamental plane of black hole activity at VLBI scales (e.g., few milli-arcsecond). The jet luminosity and size distribution among our sample roughly fit into the proposed AGN evolutionary scenario, finding powerful jets after the blow-out phase based on the Eddington ratio (\lambda_{Edd})-hydrogen column density (N_{H}) relation. In addition, we find some hints of gas inflow or galaxy-galaxy merger in the majority of our sample. This implies that gas supply via tidal interactions in galactic scale may help the central AGN to launch a powerful parsec-scale jet., Comment: 11+2 pages, 6 figures, Accepted for publication in MNRAS, Comments are welcome
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- 2019
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32. Astro2020 APC White Paper: The Early Career Perspective on the Coming Decade, Astrophysics Career Paths, and the Decadal Survey Process
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Moravec, Emily, Czekala, Ian, Follette, Kate, Ahmed, Zeeshan, Alpaslan, Mehmet, Amon, Alexandra, Armentrout, Will, Arney, Giada, Barron, Darcy, Bellm, Eric, Bender, Amy, Bridge, Joanna, Colon, Knicole, Datta, Rahul, DeRoo, Casey, Feng, Wanda, Florian, Michael, Gabriel, Travis, Hall, Kirsten, Hamden, Erika, Hathi, Nimish, Hawkins, Keith, Hoadley, Keri, Jensen-Clem, Rebecca, Kao, Melodie, Kara, Erin, Karkare, Kirit, Kiessling, Alina, Kimball, Amy, Kirkpatrick, Allison, La Plante, Paul, Leisenring, Jarron, Li, Miao, Lomax, Jamie, Lund, Michael B., McCleary, Jacqueline, Mills, Elisabeth, Montiel, Edward, Nelson, Nicholas, Nevin, Rebecca, Norris, Ryan, Ntampaka, Michelle, O'Donnell, Christine, Peretz, Eliad, Malagon, Andres Plazas, Prescod-Weinstein, Chanda, Pullen, Anthony, Rice, Jared, Roettenbacher, Rachael, Sanderson, Robyn, Simon, Jospeh, Smith, Krista Lynne, Stevenson, Kevin, Veach, Todd, Wetzel, Andrew, and Youngblood, Allison
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
In response to the need for the Astro2020 Decadal Survey to explicitly engage early career astronomers, the National Academies of Sciences, Engineering, and Medicine hosted the Early Career Astronomer and Astrophysicist Focus Session (ECFS) on October 8-9, 2018 under the auspices of Committee of Astronomy and Astrophysics. The meeting was attended by fifty six pre-tenure faculty, research scientists, postdoctoral scholars, and senior graduate students, as well as eight former decadal survey committee members, who acted as facilitators. The event was designed to educate early career astronomers about the decadal survey process, to solicit their feedback on the role that early career astronomers should play in Astro2020, and to provide a forum for the discussion of a wide range of topics regarding the astrophysics career path. This white paper presents highlights and themes that emerged during two days of discussion. In Section 1, we discuss concerns that emerged regarding the coming decade and the astrophysics career path, as well as specific recommendations from participants regarding how to address them. We have organized these concerns and suggestions into five broad themes. These include (sequentially): (1) adequately training astronomers in the statistical and computational techniques necessary in an era of "big data", (2) responses to the growth of collaborations and telescopes, (3) concerns about the adequacy of graduate and postdoctoral training, (4) the need for improvements in equity and inclusion in astronomy, and (5) smoothing and facilitating transitions between early career stages. Section 2 is focused on ideas regarding the decadal survey itself, including: incorporating early career voices, ensuring diverse input from a variety of stakeholders, and successfully and broadly disseminating the results of the survey., Comment: 9 pages; Astro2020 APC White Paper: State of the Profession Consideration
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- 2019
33. The Vast Potential of Exoplanet Satellites for High-Energy Astrophysics
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Smith, Krista Lynne
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
The photometric precision, monitoring baselines, and rapid, even sampling rates required by modern satellites designed for detecting the signal of transiting exoplanets are ideally suited to a large number of applications in high-energy astrophysics. I will exemplify this by discussing the results for active galactic nuclei from Kepler and summarizing other high-energy results from Kepler/K2. These precision instruments are currently underutilized for high-energy applications despite their great potential, due in part to complex systematics affecting the data. I will summarize these effects and mitigation approaches, and conclude by discussing how the recently launched Transiting Exoplanet Survey Satellite mission will differ from Kepler/K2 in ways significant to the high-energy community., Comment: Accepted for publication in Astronomische Nachrichten. Conference Proceedings from "Time-Domain Astronomy: A High Energy View", June 13-15 2018, ESAC, Madrid, Spain
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- 2019
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34. STROBE-X: X-ray Timing and Spectroscopy on Dynamical Timescales from Microseconds to Years
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Ray, Paul S., Arzoumanian, Zaven, Ballantyne, David, Bozzo, Enrico, Brandt, Soren, Brenneman, Laura, Chakrabarty, Deepto, Christophersen, Marc, DeRosa, Alessandra, Feroci, Marco, Gendreau, Keith, Goldstein, Adam, Hartmann, Dieter, Hernanz, Margarita, Jenke, Peter, Kara, Erin, Maccarone, Tom, McDonald, Michael, Nowak, Michael, Phlips, Bernard, Remillard, Ron, Stevens, Abigail, Tomsick, John, Watts, Anna, Wilson-Hodge, Colleen, Wood, Kent, Zane, Silvia, Ajello, Marco, Alston, Will, Altamirano, Diego, Antoniou, Vallia, Arur, Kavitha, Ashton, Dominic, Auchettl, Katie, Ayres, Tom, Bachetti, Matteo, Balokovic, Mislav, Baring, Matthew, Baykal, Altan, Begelman, Mitch, Bhat, Narayana, Bogdanov, Slavko, Briggs, Michael, Bulbul, Esra, Bult, Petrus, Burns, Eric, Cackett, Ed, Campana, Riccardo, Caspi, Amir, Cavecchi, Yuri, Chenevez, Jerome, Cherry, Mike, Corbet, Robin, Corcoran, Michael, Corsi, Alessandra, Degenaar, Nathalie, Drake, Jeremy, Eikenberry, Steve, Enoto, Teruaki, Fragile, Chris, Fuerst, Felix, Gandhi, Poshak, Garcia, Javier, Gonzalez, Anthony, Grefenstette, Brian, Grinberg, Victoria, Grossan, Bruce, Guillot, Sebastien, Guver, Tolga, Haggard, Daryl, Heinke, Craig, Heinz, Sebastian, Hemphill, Paul, Homan, Jeroen, Hui, Michelle, Huppenkothen, Daniela, Ingram, Adam, Irwin, Jimmy, Jaisawal, Gaurava, Jaodand, Amruta, Kalemci, Emrah, Kaplan, David, Keek, Laurens, Kennea, Jamie, Kerr, Matthew, van der Klis, Michiel, Kocevski, Daniel, Koss, Mike, Kowalski, Adam, Lai, Dong, Lamb, Fred, Laycock, Silas, Lazio, Joseph, Lazzati, Davide, Longcope, Dana, Loewenstein, Michael, Maitra, Dipankair, Majid, Walid, Maksym, W. Peter, Malacaria, Christian, Margutti, Raffaella, Martindale, Adrian, McHardy, Ian, Meyer, Manuel, Middleton, Matt, Miller, Jon, Miller, Cole, Motta, Sara, Neilsen, Joey, Nelson, Tommy, Noble, Scott, O'Brien, Paul, Osborne, Julian, Osten, Rachel, Ozel, Feryal, Palliyaguru, Nipuni, Pasham, Dheeraj, Patruno, Alessandro, Pelassa, Vero, Petropoulou, Maria, Pilia, Maura, Pohl, Martin, Pooley, David, Prescod-Weinstein, Chanda, Psaltis, Dimitrios, Raaijmakers, Geert, Reynolds, Chris, Riley, Thomas E., Salvesen, Greg, Santangelo, Andrea, Scaringi, Simone, Schanne, Stephane, Schnittman, Jeremy, Smith, David, Smith, Krista Lynne, Snios, Bradford, Steiner, Andrew, Steiner, Jack, Stella, Luigi, Strohmayer, Tod, Sun, Ming, Tauris, Thomas, Taylor, Corbin, Tohuvavohu, Aaron, Vacchi, Andrea, Vasilopoulos, Georgios, Veledina, Alexandra, Walsh, Jonelle, Weinberg, Nevin, Wilkins, Dan, Willingale, Richard, Wilms, Joern, Winter, Lisa, Wolff, Michael, Zand, Jean in 't, Zezas, Andreas, Zhang, Bing, and Zoghbi, Abdu
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X), a probe-class mission concept selected for study by NASA. It combines huge collecting area, high throughput, broad energy coverage, and excellent spectral and temporal resolution in a single facility. STROBE-X offers an enormous increase in sensitivity for X-ray spectral timing, extending these techniques to extragalactic targets for the first time. It is also an agile mission capable of rapid response to transient events, making it an essential X-ray partner facility in the era of time-domain, multi-wavelength, and multi-messenger astronomy. Optimized for study of the most extreme conditions found in the Universe, its key science objectives include: (1) Robustly measuring mass and spin and mapping inner accretion flows across the black hole mass spectrum, from compact stars to intermediate-mass objects to active galactic nuclei. (2) Mapping out the full mass-radius relation of neutron stars using an ensemble of nearly two dozen rotation-powered pulsars and accreting neutron stars, and hence measuring the equation of state for ultradense matter over a much wider range of densities than explored by NICER. (3) Identifying and studying X-ray counterparts (in the post-Swift era) for multiwavelength and multi-messenger transients in the dynamic sky through cross-correlation with gravitational wave interferometers, neutrino observatories, and high-cadence time-domain surveys in other electromagnetic bands. (4) Continuously surveying the dynamic X-ray sky with a large duty cycle and high time resolution to characterize the behavior of X-ray sources over an unprecedentedly vast range of time scales. STROBE-X's formidable capabilities will also enable a broad portfolio of additional science., Comment: 50 pages, Probe class mission concept study report submitted to NASA for Astro2020 Decadal Survey
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- 2019
35. Leading with Compassion: Co-designing a Workshop That Responds to a Report of Sexual Harassment or Discrimination with Unbiased Compassion
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Price, Shelley T., author, Fogarty, Megan, author, Sheppard, De-Ann, author, Campbell, Grace, author, Cartwright, Sarah, author, Ito, Kylie, author, MacDonald, Rachel, author, Skotnitsky, Sabrina Guzman, author, Weigand, Heidi, author, and Smith, Krista, author
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- 2022
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36. Evidence for an Optical Low-frequency Quasi-Periodic Oscillation in the Kepler Light Curve of an Active Galaxy
- Author
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Smith, Krista Lynne, Mushotzky, Richard F., Boyd, Patricia T., and Wagoner, Robert V.
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report evidence for a quasi-periodic oscillation (QPO) in the optical light curve of KIC 9650712, a narrow-line Seyfert 1 galaxy in the original Kepler field. After the development and application of a pipeline for Kepler data specific to active galactic nuclei (AGN), one of our sample of 21 AGN selected by infrared photometry and X-ray flux demonstrates a peak in the power spectrum at log $\nu$ = -6.58 Hz, corresponding to a temporal period of t=44 days. We note that although the power spectrum is well-fit by a model consisting of a Lorentzian and a single power law, alternative continuum models cannot be ruled out. From optical spectroscopy, we measure the black hole mass of this AGN as log $M_{\mathrm{BH}} / M_\odot$ = 8.17. We find that this frequency lies along a correlation between low-frequency QPOs and black hole mass from stellar and intermediate mass black holes to AGN, similar to the known correlation in high-frequency QPOs., Comment: 6 pages, 4 figures, Accepted for Publication in ApJ Letters
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- 2018
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37. The mm-wave compact component of AGN
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Behar, Ehud, Vogel, Stuart, Baldi, Ranieri D., Smith, Krista L., and Mushotzky, Richard F.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
mm-wave emission from Active Galactic Nuclei (AGN) may hold the key to understanding the physical origin of their radio cores. The correlation between radio/mm and X-ray luminosity may suggest a similar physical origin of the two sources. Since synchrotron self absorption decreases with frequency, mm-waves probe smaller length scales than cm-waves. We report on 100 GHz (3 mm) observations with CARMA of 26 AGNs selected from the hard X-ray Swift/BAT survey. 20/26 targets were detected at 100 GHz down to the 1 mJy (3 $\sigma$) sensitivity, which corresponds to optically thick synchrotron source sizes of 10$^{-4}$ - 10$^{-3}$ pc). Most sources show a 100 GHz flux excess with respect to the spectral slope extrapolated from low frequencies. This mm spectral component likely originates from smaller scales than the few-GHz emission. The measured mm sources lie roughly around the L$_{mm}$ (100 GHz) $\sim$ 10$^{-1}$ L$_{X}$ (2-10 keV) relation, similar to a few previously published X-ray selected sources, and hinting perhaps at a common coronal origin., Comment: submitted to MNRAS, revised by the referee, comments welcome (9 pages, 4 figures)
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- 2018
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38. The Kepler Light Curves of AGN: A Detailed Analysis
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Smith, Krista Lynne, Mushotzky, Richard F., Boyd, Patricia T., Malkan, Matt, Howell, Steve B., and Gelino, Dawn M.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present a comprehensive analysis of 21 light curves of Type 1 AGN from the Kepler spacecraft. First, we describe the necessity and development of a customized pipeline for treating Kepler data of stochastically variable sources like AGN. We then present the light curves, power spectral density functions (PSDs), and flux histograms. The light curves display an astonishing variety of behaviors, many of which would not be detected in ground-based studies, including switching between distinct flux levels. Six objects exhibit PSD flattening at characteristic timescales which roughly correlate with black hole mass. These timescales are consistent with orbital timescales or freefall accretion timescales. We check for correlations of variability and high-frequency PSD slope with accretion rate, black hole mass, redshift and luminosity. We find that bolometric luminosity is anticorrelated with both variability and steepness of the PSD slope. We do not find evidence of the linear rms-flux relationships or lognormal flux distributions found in X-ray AGN light curves, indicating that reprocessing is not a significant contributor to optical variability at the 0.1-10% level., Comment: 39 pages including 2 appendices. Accepted for Publication in the Astrophysical Journal, with higher resolution figures
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- 2018
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39. Baseline human gut microbiota profile in healthy people and standard reporting template.
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King, Charles H, Desai, Hiral, Sylvetsky, Allison C, LoTempio, Jonathan, Ayanyan, Shant, Carrie, Jill, Crandall, Keith A, Fochtman, Brian C, Gasparyan, Lusine, Gulzar, Naila, Howell, Paul, Issa, Najy, Krampis, Konstantinos, Mishra, Lopa, Morizono, Hiroki, Pisegna, Joseph R, Rao, Shuyun, Ren, Yao, Simonyan, Vahan, Smith, Krista, VedBrat, Sharanjit, Yao, Michael D, and Mazumder, Raja
- Subjects
Feces ,Humans ,Metagenome ,Metagenomics ,Gastrointestinal Microbiome ,General Science & Technology - Abstract
A comprehensive knowledge of the types and ratios of microbes that inhabit the healthy human gut is necessary before any kind of pre-clinical or clinical study can be performed that attempts to alter the microbiome to treat a condition or improve therapy outcome. To address this need we present an innovative scalable comprehensive analysis workflow, a healthy human reference microbiome list and abundance profile (GutFeelingKB), and a novel Fecal Biome Population Report (FecalBiome) with clinical applicability. GutFeelingKB provides a list of 157 organisms (8 phyla, 18 classes, 23 orders, 38 families, 59 genera and 109 species) that forms the baseline biome and therefore can be used as healthy controls for studies related to dysbiosis. This list can be expanded to 863 organisms if closely related proteomes are considered. The incorporation of microbiome science into routine clinical practice necessitates a standard report for comparison of an individual's microbiome to the growing knowledgebase of "normal" microbiome data. The FecalBiome and the underlying technology of GutFeelingKB address this need. The knowledgebase can be useful to regulatory agencies for the assessment of fecal transplant and other microbiome products, as it contains a list of organisms from healthy individuals. In addition to the list of organisms and their abundances, this study also generated a collection of assembled contiguous sequences (contigs) of metagenomics dark matter. In this study, metagenomic dark matter represents sequences that cannot be mapped to any known sequence but can be assembled into contigs of 10,000 nucleotides or higher. These sequences can be used to create primers to study potential novel organisms. All data is freely available from https://hive.biochemistry.gwu.edu/gfkb and NCBI's Short Read Archive.
- Published
- 2019
40. Rapid multi-band space-based optical timing: revolutionizing accretion physics
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Smith, Krista Lynne, primary
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- 2024
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41. Radio Properties of the BAT AGN: the FIR-Radio Relation, the Fundamental Plane, and the Main Sequence of Star Formation
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Smith, Krista Lynne, Mushotzky, Richard F., Vogel, Stuart, Shimizu, Thomas T., and Miller, Neal
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Astrophysics - Astrophysics of Galaxies - Abstract
We have conducted 22 GHz 1" JVLA imaging of 70 radio-quiet AGN from the Swift-BAT survey. We find radio cores in all but three objects. The radio morphologies of the sample fall into three groups: compact and core-dominated, extended, and jet-like. We spatially decompose each image into core flux and extended flux, and compare the extended radio emission to that predicted from previous Herschel observations using the canonical FIR-radio relation. After removing the AGN contribution to the FIR and radio flux densities, we find that the relation holds remarkably well despite the potentially different star formation physics in the circumnuclear environment. We also compare our core radio flux densities with predictions of coronal models and scale-invariant jet models for the origin of radio emission in radio-quiet AGN, and find general consistency with both models. However, we find that the $L_{\mathrm{R}} / L_{\mathrm{X}}$ relation does not distinguish between star formation and non-relativistic AGN-driven outflows as the origin of radio emission in radio-quiet AGN. Finally, we examine where objects with different radio morphologies fall in relation to the main sequence of star formation, and conclude that those AGN that fall below the main sequence, as X-ray selected AGN have been found to do, have core-dominated or jet-like 22 GHz morphologies., Comment: 17 pages, 9 figures, accepted for publication in the Astrophysical Journal
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- 2016
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42. Rapidly Rotating, X-ray Bright Stars in the Kepler Field
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Howell, Steve B., Mason, Elena, Boyd, Padi, Smith, Krista Lynne, and Gelino, Dawn
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We present Kepler light curves and optical spectroscopy of twenty X-ray bright stars located in the Kepler field of view. The stars, spectral type FK, show evidence for rapid rotation including chromospheric activity 100 times or more above the Sun at maximum and flaring behavior in their light curves. Eighteen of our objects appear to be (sub)giants and may belong to the class of FK Com variables, that is evolved rapidly spinning single stars with no excretion disk and high levels of chromospheric activity. Such stars are rare and are likely the result of W UMa binary mergers, a process believed to produce the FK Com class of variable and their descendants. The FK Com stage, including the presence of an excretion disk, is short-lived but leads to longer-lived stages consisting of single, rapidly rotating evolved (sub)giants with high levels of stellar activity., Comment: 34 pages, Accepted in ApJ
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- 2016
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43. Experiences with Classism: A Look at Social Class in a Rural High School
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Pietrantoni, Zachary, Glance, Dorea, and Smith, Krista M.
- Abstract
The American School Counselor Association's (ASCA) National Model (2012) stated school counselors serve as advocates for equity in access and success in educational opportunities for all students; however, Lott (2002) suggested classism now affects more students than in previous generations. Most research has focused on college students and little research has addressed the experiences with classism for high school students. The researchers addressed this gap through an ethnographic qualitative study on experiences with classism of a rural high school in Illinois. The researchers concluded with implications for school counselors and future research on the area of classism in high schools.
- Published
- 2015
44. KSwAGS: A Swift X-ray and UV Survey of the Kepler Field. I
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Smith, Krista Lynne, Boyd, Patricia T., Mushotzky, Richard F., Gehrels, Neil, Edelson, Rick, Howell, Steve B., Gelino, Dawn M., Brown, Alexander, and Young, Steve
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We introduce the first phase of the Kepler-Swift Active Galaxies and Stars survey (KSwAGS), a simultaneous X-ray and UV survey of ~6 square degrees of the Kepler field using the Swift XRT and UVOT. We detect 93 unique X-ray sources with S/N>3 with the XRT, of which 60 have observed UV counterparts. We use the Kepler Input Catalog (KIC) to obtain the optical counterparts of these sources, and construct the X-ray to optical flux ratio as a first approximation of the classification of the source. The survey produces a mixture of stellar sources, extragalactic sources, and sources which we are not able to classify with certainty. We have obtained optical spectra for thirty of these targets, and are conducting an ongoing observing campaign to fully identify the sample. For sources classified as stellar or AGN with certainty, we construct SEDs using the 2MASS, UBV and GALEX data supplied for their optical counterparts by the KIC, and show that the SEDs differ qualitatively between the source types, and so can offer a method of classification in absence of a spectrum. Future papers in this series will analyze the timing properties of the stars and AGN in our sample separately. Our survey provides the first X-ray and UV data for a number of known variable stellar sources, as well as a large number of new X-ray detections in this well-studied portion of the sky. The KSwAGS survey is currently ongoing in the K2 ecliptic plane fields., Comment: Accepted for publication in the Astronomical Journal. 19 pages, 8 figures, 3 tables
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- 2015
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45. Leading with Compassion: Co-designing a Workshop That Responds to a Report of Sexual Harassment or Discrimination with Unbiased Compassion
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Price, Shelley T., primary, Fogarty, Megan, additional, Sheppard, De-Ann, additional, Campbell, Grace, additional, Cartwright, Sarah, additional, Ito, Kylie, additional, MacDonald, Rachel, additional, Skotnitsky, Sabrina Guzman, additional, Weigand, Heidi, additional, and Smith, Krista, additional
- Published
- 2022
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46. Search for quasi-periodic oscillations in TESS light curves of bright Fermi Blazars
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Tripathi, Ashutosh, primary, Smith, Krista Lynne, additional, Wiita, Paul J, additional, and Wagoner, Robert V, additional
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- 2024
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47. Discovery of a ~5 day characteristic timescale in the Kepler power spectrum of Zw 229-15
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Edelson, Rick, Vaughan, Simon, Malkan, Matt, Kelly, Brandon, Smith, Krista, Boyd, Padi, and Mushotzky, Richard
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present time series analyses of the full Kepler dataset of Zw 229-15. This Kepler light curve --- with a baseline greater than three years, composed of virtually continuous, evenly sampled 30-minute measurements --- is unprecedented in its quality and precision. We utilize two methods of power spectral analysis to investigate the optical variability and search for evidence of a bend frequency associated with a characteristic optical variability timescale. Each method yields similar results. The first interpolates across data gaps to use the standard Fourier periodogram. The second, using the CARMA-based time-domain modeling technique of Kelly et al. (2014), does not need evenly-sampled data. Both methods find excess power at high frequencies that may be due to Kepler instrumental effects. More importantly both also show strong bends ({\Delta}{\alpha} ~ 2) at timescales of ~5 days, a feature similar to those seen in the X-ray PSDs of AGN but never before in the optical. This observed ~5 day timescale may be associated with one of several physical processes potentially responsible for the variability. A plausible association could be made with light-crossing, dynamical or thermal timescales, depending on the assumed value of the accretion disk size and on unobserved disk parameters such as {\alpha} and H/R. This timescale is not consistent with the viscous timescale, which would be years in a ~10^7 Solar mass AGN such as Zw 229-15. However there must be a second bend on long (>~1 year) timescales, and that feature could be associated with the viscous timescale., Comment: 10 pages, 5 figures, 1 table. To appear in the Astrophysical Journal, Part 1
- Published
- 2014
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48. An Infrared and Optical Analysis of a Sample of XBONGs and Optically Elusive AGN
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Smith, Krista Lynne, Koss, Michael, and Mushotzky, Richard F.
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Astrophysics - Astrophysics of Galaxies - Abstract
We present near-infrared (NIR) spectra of four optically-elusive AGN and four X- ray bright, optically normal galaxies (XBONGs) from the Swift-BAT survey. With archival observations from SDSS, 2MASS, Spitzer and WISE, we test a number of AGN indicators in the NIR and MIR; namely, NIR emission line diagnostic ratios, the presence of coronal high-ionization lines, and infrared photometry. Of our eight hard X-ray selected AGN, we find that optical normalcy has a variety of causes from object to object, and no one explanation applies. Our objects have normal Eddington ratios, and so are unlikely to host radiatively-inefficient accretion flows (RIAFs). It is unlikely that star formation in the host or starlight dilution is contributing to their failure of optical diagnostics, except perhaps in two cases. The NIR continua are well-fit by two blackbodies: one at the stellar temperature, and a hot dust component near the dust sublimation temperature. XBONGs are more likely to have significant hot dust components, while these components are small relative to starlight in the optically-elusive AGN. Some of our sample have NIR line ratios typical of AGN, but NIR diagnostics are unsuccessful in distinguishing HII regions from AGN in general. In one object, we discover a hidden broad line region in the NIR. These results have strong relevance to the origin of optically normal AGN in deep X-ray surveys., Comment: 38 pages including 3 tables and 11 figures, Accepted for publication in ApJ
- Published
- 2014
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49. Reverberation Mapping of the Kepler-Field AGN KA1858+4850
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Pei, Liuyi, Barth, Aaron J., Aldering, Greg S., Briley, Michael M., Carroll, Carla J., Carson, Daniel J., Cenko, S. Bradley, Clubb, Kelsey I., Cohen, Daniel P., Cucchiara, Antonino, Desjardins, Tyler D., Edelson, Rick, Fang, Jerome J., Fedrow, Joseph M., Filippenko, Alexei V., Fox, Ori D., Furniss, Amy, Gates, Elinor L., Gregg, Michael, Gustafson, Scott, Horst, J. Chuck, Joner, Michael D., Kelly, Patrick L., Lacy, Mark, Laney, C. David, Leonard, Douglas C., Li, Weidong, Malkan, Matthew A., Margon, Bruce, Neeleman, Marcel, Nguyen, My L., Prochaska, J. Xavier, Ross, Nathaniel R., Sand, David J., Searcy, Kinchen J., Shivvers, Isaac S., Silverman, Jeffrey M., Smith, Graeme H., Suzuki, Nao, Smith, Krista Lynne, Tytler, David, Werk, Jessica K., and Worseck, Gabor
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V-band images from five other ground-based telescopes. We measured the H-beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of lag_CCF = 13.53 (+2.03, -2.32) days and lag_JAVELIN = 13.15 (+1.08, -1.00) days. The H-beta root-mean-square line profile has a width of sigma_line = 770 +/- 49 km/s. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M_BH = 8.06 (+1.59, -1.72) x 10^6 M_sun for the mass of the central black hole and an Eddington ratio of L/L_Edd ~ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei.
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- 2014
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50. MoonLITE: a CLPS-delivered NASA Astrophysics Pioneers lunar optical interferometer for sensitive, milliarcsecond observing
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Coyle, Laura E., Matsuura, Shuji, Perrin, Marshall D., van Belle, Gerard T., Ciardi, David, Hillsberry, Daniel, Jorgensen, Anders, Monnier, John, Smith, Krista Lynne, Boyajian, Tabetha, Carpenter, Kenneth, Clark, Catherine, Rau, Gioia, and Schaefer, Gail
- Published
- 2024
- Full Text
- View/download PDF
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