HIRAX: A Probe of Dark Energy and Radio Transients

L. B. Newburgh, K. Bandura, M. A. Bucher, T. C. Chang, H. C. Chiang, J. F. Cliche, R. Dave, M. Dobbs, C. Clarkson, K. M. Ganga, T. Gogo, A. Gumba, N. Gupta, M. Hilton, B. Johnstone, A. Karastergiou, M. Kunz, D. Lokhorst, R. Maartens, S. MacphersonM. Mdlalose, K. Moodley, L. Ngwenya, J. M. Parra, J. Peterson, O. Recnik, B. Saliwanchik, M. G. Santos, J. L. Sievers, O. Smirnov, P. Stronkhorst, R. Taylor, K. Vanderlinde, G. Van Vuuren, A. Weltman, A. Witzemann

Research output: Chapter in Book/Report/Conference proceedingConference contribution

172 Scopus citations


The Hydrogen Intensity and Real-Time Analysis eXperiment (HIRAX) is a new 400{800MHz radio interferometer under development for deployment in South Africa. HIRAX will comprise 1024 six meter parabolic dishes on a compact grid and will map most of the southern sky over the course of four years. HIRAX has two primary science goals: To constrain Dark Energy and measure structure at high redshift, and to study radio transients and pulsars. HIRAX will observe unresolved sources of neutral hydrogen via their redshifted 21-cm emission line ('hydrogen intensity mapping'). The resulting maps of large-scale structure at redshifts 0.8{2.5 will be used to measure Baryon Acoustic Oscillations (BAO). BAO are a preferential length scale in the matter distribution that can be used to characterize the expansion history of the Universe and thus understand the properties of Dark Energy. HIRAX will improve upon current BAO measurements from galaxy surveys by observing a larger cosmological volume (larger in both survey area and redshift range) and by measuring BAO at higher redshift when the expansion of the universe transitioned to Dark Energy domination. HIRAX will complement CHIME, a hydrogen intensity mapping experiment in the Northern Hemisphere, by completing the sky coverage in the same redshift range. HIRAX's location in the Southern Hemisphere also allows a variety of cross-correlation measurements with large-scale structure surveys at many wavelengths. Daily maps of a few thousand square degrees of the Southern Hemisphere, encompassing much of the Milky Way galaxy, will also open new opportunities for discovering and monitoring radio transients. The HIRAX correlator will have the ability to rapidly and efficiently detect transient events. This new data will shed light on the poorly understood nature of fast radio bursts (FRBs), enable pulsar monitoring to enhance long-wavelength gravitational wave searches, and provide a rich data set for new radio transient phenomena searches. This paper discusses the HIRAX instrument, science goals, and current status.

Original languageEnglish (US)
Title of host publicationGround-Based and Airborne Telescopes VI
EditorsHeather K. Marshall, Helen J. Hall, Roberto Gilmozzi
ISBN (Electronic)9781510601918
StatePublished - 2016
EventGround-Based and Airborne Telescopes VI - Edinburgh, United Kingdom
Duration: Jun 26 2016Jul 1 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherGround-Based and Airborne Telescopes VI
Country/TerritoryUnited Kingdom


  • 21cm
  • Cosmology
  • Dark energy
  • Intensity mapping
  • Large-scale structure

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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