Hydrogen epoch of reionization array (HERA)

David R. Deboer, Aaron R. Parsons, James E. Aguirre, Paul Alexander, Zaki S. Ali, Adam P. Beardsley, Gianni Bernardi, Judd Bowman, Richard F. Bradley, Chris L. Carilli, Carina Cheng, Eloy De Lera Acedo, Joshua S. Dillon, Aaron Ewall-Wice, Gcobisa Fadana, Nicolas Fagnoni, Randall Fritz, Steve R. Furlanetto, Brian Glendenning, Bradley GreigJasper Grobbelaar, Bryna J. Hazelton, Jacqueline N. Hewitt, Jack Hickish, Daniel Jacobs, Austin Julius, Maccalvin Kariseb, Saul A. Kohn, Telalo Lekalake, Adrian Liu, Anita Loots, David Macmahon, Lourence Malan, Cresshim Malgas, Matthys Maree, Zachary Martinot, Nathan Mathison, Eunice Matsetela, Andrei Mesinger, Miguel F. Morales, Abraham R. Neben, Nipanjana Patra, Samantha Pieterse, Jonathan C. Pober, Nima Razavi-Ghods, Jon Ringuette, James Robnett, Kathryn Rosie, Raddwine Sell, Craig Smith, Angelo Syce, Max Tegmark, Nithyanandan Thyagarajan, Peter K G Williams, Haoxuan Zheng

Research output: Contribution to journalArticlepeer-review

467 Scopus citations


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 ∼ 30). 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.

Original languageEnglish (US)
Article number045001
JournalPublications of the Astronomical Society of the Pacific
Issue number974
StatePublished - Apr 1 2017


  • Dark ages
  • First stars
  • Instrumentation: Interferometers
  • Reionization
  • Techniques: Interferometric
  • Telescopes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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