Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-point Statistics
Year: 2025
Type: article
Abstract: Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early Universe. We assess the impact of instrumental effects on measurements made with the Hydrogen Epoch of Reionization Array (HERA) by forward modeling observational and simulation data. Using HERA Phase I observations over 94 nights, we examine the second ( m 2 , variance) and third ( m 3 ) moments of images. We employ the DAYENU -filtering method for foreground removal and reduce simulated foreground residuals to 10% of the 21 cm signal residuals. In noiseless cosmological simulations, the amplitudes of one-point statistics measurements are significantly reduced by the instrument response and further reduced by wedge-filtering. Analyses with wedge-filtered observational data, along with expected noise simulations, show that systematics alter the probability distribution of the map pixels. A likelihood analysis based on the observational data shows m 2 measurements disfavor the cold reionization model characterized by inefficient X-ray heating, in line with other power spectra measurements. Small signals in m 3 due to the instrument response of the Phase I observation and wedge-filtering make it challenging to use these non-Gaussian statistics to explore model parameters. Forecasts with the full HERA array predict high signal-to-noise ratios for m 2 , m 3 , and S 3 assuming no foregrounds, but wedge-filtering drastically reduces these ratios. This work demonstrates conclusively that a comprehensive understanding of instrumental effects on m 2 and m 3 is essential for their use as a cosmological probe, given their dependence on the underlying model.
Source: The Astrophysical Journal
Authors: Honggeun Kim, Jacqueline N. Hewitt, Nicholas S. Kern, Joshua S. Dillon, Kai-Feng Chen, Zhilei Xu, Eleanor Rath, Vincent MacKay, Tyrone Adams, James E. Aguirre, Rushelle Baartman, Adam P. Beardsley, Gianni Bernardi, Tashalee S. Billings, Judd D. Bowman, Richard F. Bradley, Philip Bull, Jacob Burba, Steven Carey, Chris L. Carilli, David R. DeBoer, Eloy de Lera Acedo, Matt Dexter, Nico Eksteen, John Ely, Aaron Ewall-Wice, Nicolas Fagnoni, Steven R. Furlanetto, Kingsley Gale-Sides, Brian Glendenning, Deepthi Gorthi, Bradley Greig, Jasper Grobbelaar, Ziyaad Halday, Bryna J. Hazelton, Jack Hickish, Daniel C. Jacobs, Joshua Kerrigan, Piyanat Kittiwisit, Matthew Kolopanis, Adam Lanman, Paul La Plante, Adrian Liu, David H. E. MacMahon, Lourence Malan, Cresshim Malgas, Keith Malgas, Bradley Marero, Zachary E. Martinot, Andrei Mesinger, Mathakane Molewa, Miguel F. Morales, Tshegofalang Mosiane, Steven G. Murray, Hans Nuwegeld, Aaron R. Parsons, Nima Razavi-Ghods, James Robnett, Peter Sims, Craig Smith, Hilton Swarts, Nithyanandan Thyagarajan, Pieter van Wyngaarden, Haoxuan Zheng
Institutions: Massachusetts Institute of Technology, University of California, Berkeley, South African Radio Astronomy Observatory, University of Pennsylvania, Arizona State University, Winona State University, Rhodes University, Istituto di Radioastronomia di Bologna, National Institute for Astrophysics, National Radio Astronomy Observatory, University of Manchester, University of the Western Cape, University of Cambridge, University of California, Los Angeles, The University of Melbourne, University of Washington, Brown University, University of Nevada, Las Vegas, Trottier Space Institute at McGill, McGill University, Scuola Normale Superiore, Commonwealth Scientific and Industrial Research Organisation
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W4415781365