Evidence against a supervoid causing the CMB Cold Spot

Ruari Mackenzie, Tom Shanks, Malcolm N. Bremer, Yan Chuan Cai, Madusha L.P. Gunawardhana, András Kovács, Peder Norberg, Istvan Szapudi

Research output: Contribution to journalArticle

10 Citations (Scopus)


We report the results of the 2dF-VST ATLAS Cold Spot galaxy redshift survey (2CSz) based on imaging from VST ATLAS and spectroscopy from 2dF AAOmega over the core of the CMB Cold Spot. We sparsely surveyed the inner 5° radius of the Cold Spot to a limit of iAB ≤ 19.2, sampling ~7000 galaxies at z ≤ 0.4. We have found voids at z = 0.14, 0.26 and 0.30 but they are interspersed with small overdensities, and the scale of these voids is insufficient to explain the Cold Spot through the ΛCDM ISW effect. Combining with previous data out to z ~ 1, we conclude that the CMB Cold Spot could not have been imprinted by a void confined to the inner core of the Cold Spot. Additionally, we find that our 'control' field GAMA G23 shows a similarity in its galaxy redshift distribution to the Cold Spot. Since the GAMA G23 line of sight shows no evidence of a CMB temperature decrement, we conclude that the Cold Spot may have a primordial origin rather than being due to line-of-sight effects.

Original languageEnglish
Pages (from-to)2328-2338
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - Sep 11 2017


  • Cosmic background radiation
  • Galaxies: distances and redshifts
  • Large-scale structure of Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Mackenzie, R., Shanks, T., Bremer, M. N., Cai, Y. C., Gunawardhana, M. L. P., Kovács, A., Norberg, P., & Szapudi, I. (2017). Evidence against a supervoid causing the CMB Cold Spot. Monthly Notices of the Royal Astronomical Society, 470(2), 2328-2338. https://doi.org/10.1093/mnras/stx931