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

doi:10.1093/mnras/stx931

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

Authors

Ruari Mackenzie

Tom Shanks

Malcolm N. Bremer

Yan-Chuan Cai

Madusha L.P. Gunawardhana

András Kovács

Professor Peder Norberg peder.norberg@durham.ac.uk
Professor

Istvan Szapudi

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° 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.

Citation

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. https://doi.org/10.1093/mnras/stx931

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
DOI	https://doi.org/10.1093/mnras/stx931

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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.