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1. A demonstration of the effect of fringe-rate filtering in the Hydrogen Epoch of Reionization Array delay power spectrum pipeline

Author

Garsden, Hugh, Bull, Philip, Wilensky, Mike, Abdurashidova, Zuhra, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Berkhout, Lindsay M., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steven, Carilli, Chris L., Chen, Kai-Feng, Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Dynes, Scott, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Gehlot, Bharat Kumar, Ghosh, Abhik, Glendenning, Brian, Gorce, Adelie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Huang, Tian, Jacobs, Daniel C., Josaitis, Alec, Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta Devi, Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Rath, Eleanor, Razavi-Ghods, Nima, Riley, Daniel, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Storer, Dara, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Xu, Zhilei, Zheng, Haoxuan, Garsden, Hugh, Bull, Philip, Wilensky, Mike, Abdurashidova, Zuhra, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Berkhout, Lindsay M., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steven, Carilli, Chris L., Chen, Kai-Feng, Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Dynes, Scott, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Gehlot, Bharat Kumar, Ghosh, Abhik, Glendenning, Brian, Gorce, Adelie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Huang, Tian, Jacobs, Daniel C., Josaitis, Alec, Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta Devi, Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Rath, Eleanor, Razavi-Ghods, Nima, Riley, Daniel, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Storer, Dara, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Xu, Zhilei, and Zheng, Haoxuan

Abstract

Radio interferometers targeting the 21cm brightness temperature fluctuations at high redshift are subject to systematic effects that operate over a range of different timescales. These can be isolated by designing appropriate Fourier filters that operate in fringe-rate (FR) space, the Fourier pair of local sidereal time (LST). Applications of FR filtering include separating effects that are correlated with the rotating sky vs. those relative to the ground, down-weighting emission in the primary beam sidelobes, and suppressing noise. FR filtering causes the noise contributions to the visibility data to become correlated in time however, making interpretation of subsequent averaging and error estimation steps more subtle. In this paper, we describe fringe rate filters that are implemented using discrete prolate spheroidal sequences, and designed for two different purposes -- beam sidelobe/horizon suppression (the `mainlobe' filter), and ground-locked systematics removal (the `notch' filter). We apply these to simulated data, and study how their properties affect visibilities and power spectra generated from the simulations. Included is an introduction to fringe-rate filtering and a demonstration of fringe-rate filters applied to simple situations to aid understanding., Comment: 21 pages, 18 figures, submitted to Monthly Notices of the Royal Astronomical Society

Published
2024

2. Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning

Author

Berkhout, Lindsay M., Jacobs, Daniel C., Abdurashidova, Zuhra, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Chen, Kai-Feng, Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Dynes, Scott, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Garsden, Hugh, Gehlot, Bharat Kumar, Ghosh, Abhik, Glendenning, Brian, Gorce, Adelie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Huang, Tian, Josaitis, Alec, Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta Devi, Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Rath, Eleanor, Razavi-Ghods, Nima, Riley, Daniel, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Storer, Dara, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Xu, Zhilei, Berkhout, Lindsay M., Jacobs, Daniel C., Abdurashidova, Zuhra, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Chen, Kai-Feng, Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Dynes, Scott, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Garsden, Hugh, Gehlot, Bharat Kumar, Ghosh, Abhik, Glendenning, Brian, Gorce, Adelie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Huang, Tian, Josaitis, Alec, Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta Devi, Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Rath, Eleanor, Razavi-Ghods, Nima, Riley, Daniel, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Storer, Dara, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, and Xu, Zhilei

Abstract

This paper presents the design and deployment of the Hydrogen Epoch of Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements of the Epoch of Reionization. First results from the phase I array are published as of early 2022, and deployment of the phase II system is nearing completion. We describe the design of the phase II system and discuss progress on commissioning and future upgrades. As HERA is a designated Square Kilometer Array (SKA) pathfinder instrument, we also show a number of "case studies" that investigate systematics seen while commissioning the phase II system, which may be of use in the design and operation of future arrays. Common pathologies are likely to manifest in similar ways across instruments, and many of these sources of contamination can be mitigated once the source is identified.

Published
2024

3. Search for the Epoch of Reionisation with HERA: Upper Limits on the Closure Phase Delay Power Spectrum

Author

Keller, Pascal M., Nikolic, Bojan, Thyagarajan, Nithyanandan, Carilli, Chris L., Bernardi, Gianni, Charles, Ntsikelelo, Bester, Landman, Smirnov, Oleg M., Kern, Nicholas S., Dillon, Joshua S., Hazelton, Bryna J., Morales, Miguel F., Jacobs, Daniel C., Parsons, Aaron R., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hewitt, Jacqueline N., Hickish, Jack, Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nuwegeld, Hans, Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Smith, Craig, Swarts, Hilton, Van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Keller, Pascal M., Nikolic, Bojan, Thyagarajan, Nithyanandan, Carilli, Chris L., Bernardi, Gianni, Charles, Ntsikelelo, Bester, Landman, Smirnov, Oleg M., Kern, Nicholas S., Dillon, Joshua S., Hazelton, Bryna J., Morales, Miguel F., Jacobs, Daniel C., Parsons, Aaron R., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hewitt, Jacqueline N., Hickish, Jack, Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nuwegeld, Hans, Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Smith, Craig, Swarts, Hilton, Van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

Radio interferometers aiming to measure the power spectrum of the redshifted 21 cm line during the Epoch of Reionisation (EoR) need to achieve an unprecedented dynamic range to separate the weak signal from overwhelming foreground emissions. Calibration inaccuracies can compromise the sensitivity of these measurements to the effect that a detection of the EoR is precluded. An alternative to standard analysis techniques makes use of the closure phase, which allows one to bypass antenna-based direction-independent calibration. Similarly to standard approaches, we use a delay spectrum technique to search for the EoR signal. Using 94 nights of data observed with Phase I of the Hydrogen Epoch of Reionization Array (HERA), we place approximate constraints on the 21 cm power spectrum at $z=7.7$. We find at 95% confidence that the 21 cm EoR brightness temperature is $\le$(372)$^2$ "pseudo" mK$^2$ at 1.14 "pseudo" $h$ Mpc$^{-1}$, where the "pseudo" emphasises that these limits are to be interpreted as approximations to the actual distance scales and brightness temperatures. Using a fiducial EoR model, we demonstrate the feasibility of detecting the EoR with the full array. Compared to standard methods, the closure phase processing is relatively simple, thereby providing an important independent check on results derived using visibility intensities, or related., Comment: 16 pages, 14 figures, accepted for publication by MNRAS

Published
2023
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4. matvis: A matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays

Author

Kittiwisit, Piyanat, Murray, Steven G., Garsden, Hugh, Bull, Philip, Cain, Christopher, Parsons, Aaron R., Sipple, Jackson, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Berkhout, Lindsay M., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steven, Carilli, Chris L., Chen, Kai-Feng, Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Dynes, Scott, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Gehlot, Bharat Kumar, Ghosh, Abhik, Glendenning, Brian, Gorce, Adelie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Huang, Tian, Jacobs, Daniel C., Josaitis, Alec, Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta Devi, Nuwegeld, Hans, Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Rath, Eleanor, Razavi-Ghods, Nima, Riley, Daniel, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Storer, Dara, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Xu, Zhilei, Zheng, Haoxuan, Kittiwisit, Piyanat, Murray, Steven G., Garsden, Hugh, Bull, Philip, Cain, Christopher, Parsons, Aaron R., Sipple, Jackson, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Berkhout, Lindsay M., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steven, Carilli, Chris L., Chen, Kai-Feng, Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Dynes, Scott, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Gehlot, Bharat Kumar, Ghosh, Abhik, Glendenning, Brian, Gorce, Adelie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Huang, Tian, Jacobs, Daniel C., Josaitis, Alec, Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta Devi, Nuwegeld, Hans, Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Rath, Eleanor, Razavi-Ghods, Nima, Riley, Daniel, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Storer, Dara, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Xu, Zhilei, and Zheng, Haoxuan

Abstract

Detection of the faint 21 cm line emission from the Cosmic Dawn and Epoch of Reionisation will require not only exquisite control over instrumental calibration and systematics to achieve the necessary dynamic range of observations but also validation of analysis techniques to demonstrate their statistical properties and signal loss characteristics. A key ingredient in achieving this is the ability to perform high-fidelity simulations of the kinds of data that are produced by the large, many-element, radio interferometric arrays that have been purpose-built for these studies. The large scale of these arrays presents a computational challenge, as one must simulate a detailed sky and instrumental model across many hundreds of frequency channels, thousands of time samples, and tens of thousands of baselines for arrays with hundreds of antennas. In this paper, we present a fast matrix-based method for simulating radio interferometric measurements (visibilities) at the necessary scale. We achieve this through judicious use of primary beam interpolation, fast approximations for coordinate transforms, and a vectorised outer product to expand per-antenna quantities to per-baseline visibilities, coupled with standard parallelisation techniques. We validate the results of this method, implemented in the publicly-available matvis code, against a high-precision reference simulator, and explore its computational scaling on a variety of problems., Comment: 25 pages, 20 figures, submitted to RAS Techniques and Instruments, matvis is publicly available at https://github.com/HERA-Team/matvis

Published
2023

5. Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data

Author

Murphy, Geoff G., Bull, Philip, Santos, Mario G., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee, Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Cain, Christopher, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Sipple, Jackson, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Murphy, Geoff G., Bull, Philip, Santos, Mario G., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee, Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Cain, Christopher, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Sipple, Jackson, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

Observations with radio arrays that target the 21-cm signal originating from the early Universe suffer from a variety of systematic effects. An important class of these are reflections and spurious couplings between antennas. We apply a Hamiltonian Monte Carlo sampler to the modelling and mitigation of these systematics in simulated Hydrogen Epoch of Reionisation Array (HERA) data. This method allows us to form statistical uncertainty estimates for both our models and the recovered visibilities, which is an important ingredient in establishing robust upper limits on the Epoch of Reionisation (EoR) power spectrum. In cases where the noise is large compared to the EoR signal, this approach can constrain the systematics well enough to mitigate them down to the noise level for both systematics studied. Where the noise is smaller than the EoR, our modelling can mitigate the majority of the reflections with there being only a minor level of residual systematics, while cross-coupling sees essentially complete mitigation. Our approach performs similarly to existing filtering/fitting techniques used in the HERA pipeline, but with the added benefit of rigorously propagating uncertainties. In all cases it does not significantly attenuate the underlying signal., Comment: 19 pages, 14 figures, submitted to MNRAS

Published
2023

6. Direct Optimal Mapping Image Power Spectrum and its Window Functions

Author

Xu, Zhilei, Kim, Honggeun, Hewitt, Jacqueline N., Chen, Kai-Feng, Kern, Nicholas S., Rath, Elizabeth, Byrne, Ruby, Gorce, Adélie, Martinot, Zachary E., Dillon, Joshua S., Hazelton, Bryna J., Liu, Adrian, Morales, Miguel F., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Xu, Zhilei, Kim, Honggeun, Hewitt, Jacqueline N., Chen, Kai-Feng, Kern, Nicholas S., Rath, Elizabeth, Byrne, Ruby, Gorce, Adélie, Martinot, Zachary E., Dillon, Joshua S., Hazelton, Bryna J., Liu, Adrian, Morales, Miguel F., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

The key to detecting neutral hydrogen during the epoch of reionization (EoR) is to separate the cosmological signal from the dominating foreground radiation. We developed direct optimal mapping (Xu et al. 2022) to map interferometric visibilities; it contains only linear operations, with full knowledge of point spread functions from visibilities to images. Here we present an FFT-based image power spectrum and its window functions based on direct optimal mapping. We use noiseless simulation, based on the Hydrogen Epoch of Reionization Array (HERA) Phase I configuration, to study the image power spectrum properties. The window functions show $<10^{-11}$ power leakage from the foreground-dominated region into the EoR window; the 2D and 1D power spectra also verify the separation between the foregrounds and the EoR. Furthermore, we simulated visibilities from a $uv$-complete array and calculated its image power spectrum. The result shows that the foreground--EoR leakage is further suppressed below $10^{-12}$, dominated by the tapering function sidelobes; the 2D power spectrum does not show signs of the horizon wedge. The $uv$-complete result provides a reference case for future 21cm cosmology array designs., Comment: Submitted to ApJ

Published
2023

7. Direct Optimal Mapping for 21cm Cosmology: A Demonstration with the Hydrogen Epoch of Reionization Array

Author

Xu, Zhilei, Hewitt, Jacqueline N., Chen, Kai-Feng, Kim, Hongguen, Dillon, Joshua S., Kern, Nicholas S., Morales, Miguel F., Hazelton, Bryna J., Byrne, Ruby, Fagnoni, Nicolas, Acedo, Eloy de Lera, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, Van Van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Xu, Zhilei, Hewitt, Jacqueline N., Chen, Kai-Feng, Kim, Hongguen, Dillon, Joshua S., Kern, Nicholas S., Morales, Miguel F., Hazelton, Bryna J., Byrne, Ruby, Fagnoni, Nicolas, Acedo, Eloy de Lera, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, Van Van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

Motivated by the desire for wide-field images with well-defined statistical properties for 21cm cosmology, we implement an optimal mapping pipeline that computes a maximum likelihood estimator for the sky using the interferometric measurement equation. We demonstrate this direct optimal mapping with data from the Hydrogen Epoch of Reionization (HERA) Phase I observations. After validating the pipeline with simulated data, we develop a maximum likelihood figure-of-merit for comparing four sky models at 166MHz with a bandwidth of 100kHz. The HERA data agree with the GLEAM catalogs to $<$10%. After subtracting the GLEAM point sources, the HERA data discriminate between the different continuum sky models, providing most support for the model from Byrne et al. 2021. We report the computation cost for mapping the HERA Phase I data and project the computation for the HERA 320-antenna data, both are feasible with a modern server. The algorithm is broadly applicable to other interferometers, and is valid for wide-field and non-coplanar arrays., Comment: 16 pages, 10 figures, 2 tables, submitted to ApJ

Published
2022

8. Characterization Of Inpaint Residuals In Interferometric Measurements of the Epoch Of Reionization

Author

Pagano, Michael, Liu, Jing, Liu, Adrian, Kern, Nicholas S., Ewall-Wice, Aaron, Bull, Philip, Pascua, Robert, Ravanbakhsh, Siamak, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Eksteen, Nico, Ely, John, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Pagano, Michael, Liu, Jing, Liu, Adrian, Kern, Nicholas S., Ewall-Wice, Aaron, Bull, Philip, Pascua, Robert, Ravanbakhsh, Siamak, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Eksteen, Nico, Ely, John, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

Radio Frequency Interference (RFI) is one of the systematic challenges preventing 21cm interferometric instruments from detecting the Epoch of Reionization. To mitigate the effects of RFI on data analysis pipelines, numerous inpaint techniques have been developed to restore RFI corrupted data. We examine the qualitative and quantitative errors introduced into the visibilities and power spectrum due to inpainting. We perform our analysis on simulated data as well as real data from the Hydrogen Epoch of Reionization Array (HERA) Phase 1 upper limits. We also introduce a convolutional neural network that capable of inpainting RFI corrupted data in interferometric instruments. We train our network on simulated data and show that our network is capable at inpainting real data without requiring to be retrained. We find that techniques that incorporate high wavenumbers in delay space in their modeling are best suited for inpainting over narrowband RFI. We also show that with our fiducial parameters Discrete Prolate Spheroidal Sequences (DPSS) and CLEAN provide the best performance for intermittent ``narrowband'' RFI while Gaussian Progress Regression (GPR) and Least Squares Spectral Analysis (LSSA) provide the best performance for larger RFI gaps. However we caution that these qualitative conclusions are sensitive to the chosen hyperparameters of each inpainting technique. We find these results to be consistent in both simulated and real visibilities. We show that all inpainting techniques reliably reproduce foreground dominated modes in the power spectrum. Since the inpainting techniques should not be capable of reproducing noise realizations, we find that the largest errors occur in the noise dominated delay modes. We show that in the future, as the noise level of the data comes down, CLEAN and DPSS are most capable of reproducing the fine frequency structure in the visibilities of HERA data., Comment: 21 pages, 13 figures

Published
2022
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9. Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations

Author

The HERA Collaboration, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Barkana, Rennan, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Breitman, Daniela, Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fialkov, Anastasia, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Garsden, Hugh, Glendenning, Brian, Gorce, Adélie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Heimersheim, Stefan, Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lewis, David, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Keith, Malgas, Cresshim, Maree, Matthys, Marero, Bradley, Martinot, Zachary E., McBride, Lisa, Mesinger, Andrei, Mirocha, Jordan, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Muñoz, Julian B., Murray, Steven G., Nagpal, Vighnesh, Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta D., Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Smith, Craig, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, Wilensky, Michael J., Williams, Peter K. G., van Wyngaarden, Pieter, Zheng, Haoxuan, The HERA Collaboration, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Barkana, Rennan, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Breitman, Daniela, Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fialkov, Anastasia, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Garsden, Hugh, Glendenning, Brian, Gorce, Adélie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Heimersheim, Stefan, Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lewis, David, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Keith, Malgas, Cresshim, Maree, Matthys, Marero, Bradley, Martinot, Zachary E., McBride, Lisa, Mesinger, Andrei, Mirocha, Jordan, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Muñoz, Julian B., Murray, Steven G., Nagpal, Vighnesh, Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta D., Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Smith, Craig, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, Wilensky, Michael J., Williams, Peter K. G., van Wyngaarden, Pieter, and Zheng, Haoxuan

Abstract

We report the most sensitive upper limits to date on the 21 cm epoch of reionization power spectrum using 94 nights of observing with Phase I of the Hydrogen Epoch of Reionization Array (HERA). Using similar analysis techniques as in previously reported limits (HERA Collaboration 2022a), we find at 95% confidence that $\Delta^2(k = 0.34$ $h$ Mpc$^{-1}$) $\leq 457$ mK$^2$ at $z = 7.9$ and that $\Delta^2 (k = 0.36$ $h$ Mpc$^{-1}) \leq 3,496$ mK$^2$ at $z = 10.4$, an improvement by a factor of 2.1 and 2.6 respectively. These limits are mostly consistent with thermal noise over a wide range of $k$ after our data quality cuts, despite performing a relatively conservative analysis designed to minimize signal loss. Our results are validated with both statistical tests on the data and end-to-end pipeline simulations. We also report updated constraints on the astrophysics of reionization and the cosmic dawn. Using multiple independent modeling and inference techniques previously employed by HERA Collaboration (2022b), we find that the intergalactic medium must have been heated above the adiabatic cooling limit at least as early as $z = 10.4$, ruling out a broad set of so-called "cold reionization" scenarios. If this heating is due to high-mass X-ray binaries during the cosmic dawn, as is generally believed, our result's 99% credible interval excludes the local relationship between soft X-ray luminosity and star formation and thus requires heating driven by evolved low-metallicity stars., Comment: 57 pages, 37 figures. Updated to match the accepted ApJ version. Corresponding author: Joshua S. Dillon

Published
2022
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10. Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum

Author

Gorce, Adélie, Ganjam, Samskruthi, Liu, Adrian, Murray, Steven G., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Gorce, Adélie, Ganjam, Samskruthi, Liu, Adrian, Murray, Steven G., Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Loots, Anita, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process. In a delay-based analysis, the mapping between instrumental and cosmological space is not a one-to-one relation. Instead, neighbouring modes contribute to the power measured at one point, with their respective contributions encoded in the window functions. To better understand the power measured by an interferometer, we assess the impact of instrument characteristics and analysis choices on these window functions. Focusing on the Hydrogen Epoch of Reionization Array (HERA) as a case study, we find that long-baseline observations correspond to enhanced low-k tails of the window functions, which facilitate foreground leakage, whilst an informed choice of bandwidth and frequency taper can reduce said tails. With simple test cases and realistic simulations, we show that, apart from tracing mode mixing, the window functions help accurately reconstruct the power spectrum estimator of simulated visibilities. The window functions depend strongly on the beam chromaticity, and less on its spatial structure - a Gaussian approximation, ignoring side lobes, is sufficient. Finally, we investigate the potential of asymmetric window functions, down-weighting the contribution of low-k power to avoid foreground leakage. The window functions presented here correspond to the latest HERA upper limits for the full Phase I data. They allow an accurate reconstruction of the power spectrum measured by the instrument and will be used in future analyses to confront theoretical models and data directly in cylindrical space., Comment: 18 pages, 19 figures, accepted for publication in MNRAS

Published
2022
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11. Direct Optimal Mapping for 21cm Cosmology: A Demonstration with the Hydrogen Epoch of Reionization Array

Author

Xu, Zhilei, Hewitt, Jacqueline N., Chen, Kai-Feng, Kim, Honggeun, Dillon, Joshua S., Kern, Nicholas S., Morales, Miguel F., Hazelton, Bryna J., Byrne, Ruby, Fagnoni, Nicolas, Acedo, Eloy de Lera, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, Van Van Wyngaarden, Pieter, Williams, Peter K. G., Zheng, Haoxuan, Xu, Zhilei, Hewitt, Jacqueline N., Chen, Kai-Feng, Kim, Honggeun, Dillon, Joshua S., Kern, Nicholas S., Morales, Miguel F., Hazelton, Bryna J., Byrne, Ruby, Fagnoni, Nicolas, Acedo, Eloy de Lera, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Eksteen, Nico, Ely, John, Ewall-Wice, Aaron, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, MacCalvin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Liu, Adrian, Loots, Anita, Ma, Yin-zhe, MacMahon, David Harold Edward, Malan, Lourence, Malgas, Cresshim, Malgas, Keith, Marero, Bradley, Martinot, Zachary E., Mesinger, Andrei, Molewa, Mathakane, Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nuwegeld, Hans, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Swarts, Hilton, Thyagarajan, Nithyanandan, Van Van Wyngaarden, Pieter, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

Motivated by the desire for wide-field images with well-defined statistical properties for 21cm cosmology, we implement an optimal mapping pipeline that computes a maximum likelihood estimator for the sky using the interferometric measurement equation. We demonstrate this direct optimal mapping with data from the Hydrogen Epoch of Reionization (HERA) Phase I observations. After validating the pipeline with simulated data, we develop a maximum likelihood figure-of-merit for comparing four sky models at 166MHz with a bandwidth of 100kHz. The HERA data agree with the GLEAM catalogs to <10%. After subtracting the GLEAM point sources, the HERA data discriminate between the different continuum sky models, providing most support for the model of Byrne et al. 2021. We report the computation cost for mapping the HERA Phase I data and project the computation for the HERA 320-antenna data; both are feasible with a modern server. The algorithm is broadly applicable to other interferometers and is valid for wide-field and non-coplanar arrays., Comment: 16 pages, 10 figures, 2 tables, published on ApJ

Published
2022
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