Search for the Epoch of Reionisation with HERA: Upper Limits on the Closure Phase Delay Power Spectrum
Creators: name: Keller, Pascal M.
name: Nikolic, Bojan
name: Thyagarajan, Nithyanandan
name: Carilli, Chris L.
name: Bernardi, Gianni
name: Charles, Ntsikelelo
name: Bester, Landman
name: Smirnov, Oleg M.
name: Kern, Nicholas S.
name: Dillon, Joshua S.
name: Hazelton, Bryna J.
name: Morales, Miguel F.
name: Jacobs, Daniel C.
name: Parsons, Aaron R.
name: Abdurashidova, Zara
name: Adams, Tyrone
name: Aguirre, James E.
name: Alexander, Paul
name: Ali, Zaki S.
name: Baartman, Rushelle
name: Balfour, Yanga
name: Beardsley, Adam P.
name: Billings, Tashalee S.
name: Bowman, Judd D.
name: Bradley, Richard F.
name: Bull, Philip
name: Burba, Jacob
name: Carey, Steven
name: Cheng, Carina
name: DeBoer, David R.
name: Acedo, Eloy de Lera
name: Dexter, Matt
name: Eksteen, Nico
name: Ely, John
name: Ewall-Wice, Aaron
name: Fagnoni, Nicolas
name: Fritz, Randall
name: Furlanetto, Steven R.
name: Gale-Sides, Kingsley
name: Glendenning, Brian
name: Gorthi, Deepthi
name: Greig, Bradley
name: Grobbelaar, Jasper
name: Halday, Ziyaad
name: Hewitt, Jacqueline N.
name: Hickish, Jack
name: Julius, Austin
name: Kariseb, MacCalvin
name: Kerrigan, Joshua
name: Kittiwisit, Piyanat
name: Kohn, Saul A.
name: Kolopanis, Matthew
name: Lanman, Adam
name: La Plante, Paul
name: Liu, Adrian
name: Loots, Anita
name: Ma, Yin-Zhe
name: MacMahon, David Harold Edward
name: Malan, Lourence
name: Malgas, Cresshim
name: Malgas, Keith
name: Marero, Bradley
name: Martinot, Zachary E.
name: Mesinger, Andrei
name: Molewa, Mathakane
name: Mosiane, Tshegofalang
name: Murray, Steven G.
name: Neben, Abraham R.
name: Nuwegeld, Hans
name: Pascua, Robert
name: Patra, Nipanjana
name: Pieterse, Samantha
name: Pober, Jonathan C.
name: Razavi-Ghods, Nima
name: Robnett, James
name: Rosie, Kathryn
name: Santos, Mario G.
name: Sims, Peter
name: Smith, Craig
name: Swarts, Hilton
name: Van Wyngaarden, Pieter
name: Williams, Peter K. G.
name: Zheng, Haoxuan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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.
description: 16 pages, 14 figures, accepted for publication by MNRAS