English

Evidence against a supervoid causing the CMB Cold Spot

Cosmology and Nongalactic Astrophysics 2017-07-26 v1

Abstract

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^{\circ} radius of the Cold Spot to a limit of iAB19.2i_{AB} \le 19.2, sampling 7000\sim7000 galaxies at z<0.4z<0.4. We have found voids at z=z= 0.14, 0.26 and 0.30 but they are interspersed with small over-densities and the scale of these voids is insufficient to explain the Cold Spot through the Λ\LambdaCDM ISW effect. Combining with previous data out to z1z\sim1, 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.

Cite

@article{arxiv.1704.03814,
  title  = {Evidence against a supervoid causing the CMB Cold Spot},
  author = {Ruari Mackenzie and Tom Shanks and Malcolm N. Bremer and Yan-Chuan Cai and Madusha L. P. Gunawardhana and András Kovács and Peder Norberg and Istvan Szapudi},
  journal= {arXiv preprint arXiv:1704.03814},
  year   = {2017}
}

Comments

Submitted to MNRAS

R2 v1 2026-06-22T19:15:49.994Z