THE HYDROGEN EPOCH of REIONIZATION ARRAY DISH. I. BEAM PATTERN MEASUREMENTS and SCIENCE IMPLICATIONS

Abraham R. Neben, Richard F. Bradley, Jacqueline N. Hewitt, David R. Deboer, Aaron R. Parsons, James E. Aguirre, Zaki S. Ali, Carina Cheng, Aaron Ewall-Wice, Nipanjana Patra, Nithyanandan Thyagarajan, Judd Bowman, Roger Dickenson, Joshua S. Dillon, Phillip Doolittle, Dennis Egan, Mike Hedrick, Daniel Jacobs, Saul A. Kohn, Patricia J. KlimaKavilan Moodley, Benjamin R B Saliwanchik, Patrick Schaffner, John Shelton, H. A. Taylor, Rusty Taylor, Max Tegmark, Butch Wirt, Haoxuan Zheng

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. In this paper, we focus on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m2 in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ∼ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.

Original languageEnglish (US)
Article number199
JournalAstrophysical Journal
Volume826
Issue number2
DOIs
StatePublished - Aug 1 2016

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Keywords

  • cosmology: observations
  • dark ages, reionization, first stars
  • instrumentation: interferometers

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Neben, A. R., Bradley, R. F., Hewitt, J. N., Deboer, D. R., Parsons, A. R., Aguirre, J. E., Ali, Z. S., Cheng, C., Ewall-Wice, A., Patra, N., Thyagarajan, N., Bowman, J., Dickenson, R., Dillon, J. S., Doolittle, P., Egan, D., Hedrick, M., Jacobs, D., Kohn, S. A., ... Zheng, H. (2016). THE HYDROGEN EPOCH of REIONIZATION ARRAY DISH. I. BEAM PATTERN MEASUREMENTS and SCIENCE IMPLICATIONS. Astrophysical Journal, 826(2), [199]. https://doi.org/10.3847/0004-637X/826/2/199