Cosmological performance of SKA HI galaxy surveys

S. Yahya*, P. Bull, M. G. Santos, M. Silva, R. Maartens, P. Okouma, B. Bassett

*Corresponding author for this work

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The Square Kilometre Array (SKA) will conduct the biggest spectroscopic galaxy survey ever, by detecting the 21 cm emission line of neutral hydrogen (H I) from around a billion galaxies over 3/4 of the sky, out to a redshift of z ~ 2. This will allow the redshift-space matter power spectrum, and corresponding dark energy observables, to be measured with unprecedented precision. In this paper, we present an improved model of the HI galaxy number counts and bias from semi-analytic simulations, and use it to calculate the expected yield of HI galaxies from surveys with a variety of Phase 1 and 2 SKA configurations. We illustrate the relative performance of the different surveys by forecasting errors on the radial and transverse scales of the baryon acoustic oscillation (BAO) feature, finding that the full 'billion galaxy survey' with SKA2 will deliver the largest dark energy Figure of Merit of any current or future large-scale structure survey.

Original languageEnglish
Pages (from-to)2251-2260
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Early online date6 May 2015
Publication statusPublished - 1 Jul 2015


  • Dark energy
  • RCUK
  • STFC
  • ST/K0090X/1


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