Hydrogen Epoch of Reionization Array (HERA)
Creators: name: DeBoer, David R.
name: Parsons, Aaron R.
name: Aguirre, James E.
name: Alexander, Paul
name: Ali, Zaki S.
name: Beardsley, Adam P.
name: Bernardi, Gianni
name: Bowman, Judd D.
name: Bradley, Richard F.
name: Carilli, Chris L.
name: Cheng, Carina
name: Acedo, Eloy de Lera
name: Dillon, Joshua S.
name: Ewall-Wice, Aaron
name: Fadana, Gcobisa
name: Fagnoni, Nicolas
name: Fritz, Randall
name: Furlanetto, Steve R.
name: Glendenning, Brian
name: Greig, Bradley
name: Grobbelaar, Jasper
name: Hazelton, Bryna J.
name: Hewitt, Jacqueline N.
name: Hickish, Jack
name: Jacobs, Daniel C.
name: Julius, Austin
name: Kariseb, MacCalvin
name: Kohn, Saul A.
name: Lekalake, Telalo
name: Liu, Adrian
name: Loots, Anita
name: MacMahon, David
name: Malan, Lourence
name: Malgas, Cresshim
name: Maree, Matthys
name: Mathison, Nathan
name: Matsetela, Eunice
name: Mesinger, Andrei
name: Morales, Miguel F.
name: Neben, Abraham R.
name: Patra, Nipanjana
name: Pieterse, Samantha
name: Pober, Jonathan C.
name: Razavi-Ghods, Nima
name: Ringuette, Jon
name: Robnett, James
name: Rosie, Kathryn
name: Sell, Raddwine
name: Smith, Craig
name: Syce, Angelo
name: Tegmark, Max
name: Thyagarajan, Nithyanandan
name: Williams, Peter K. G.
name: Zheng, Haoxuan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization ($z=6-12$), and to explore earlier epochs of our Cosmic Dawn ($z\sim30$). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14-m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA's scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology.
description: 26 pages, 24 figures, 2 tables