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Evidence against a supervoid causing the CMB Cold Spot

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

Evidence against a supervoid causing the CMB Cold Spot Thumbnail


Ruari Mackenzie

Tom Shanks

Malcolm N. Bremer

Yan-Chuan Cai

Madusha L.P. Gunawardhana

András Kovács

Istvan Szapudi


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.


Mackenzie, R., Shanks, T., Bremer, M. N., Cai, Y., Gunawardhana, M. L., Kovács, A., …Szapudi, I. (2017). Evidence against a supervoid causing the CMB Cold Spot. Monthly Notices of the Royal Astronomical Society, 470(2), 2328-2338.

Journal Article Type Article
Acceptance Date Apr 13, 2017
Online Publication Date Apr 25, 2017
Publication Date Sep 11, 2017
Deposit Date Aug 4, 2017
Publicly Available Date Aug 4, 2017
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 470
Issue 2
Pages 2328-2338


Published Journal Article (1.4 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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