Detection of a supervoid aligned with the cold spot of the cosmic microwave background

Szapudi, I.; Kovács, A.; Granett, B.R.; Frei, Z.; Silk, J.; Burgett, W.; Cole, S.; Draper, P.W.; Farrow, D.J.; Kaiser, N.; Magnier, E.A.; Metcalfe, N.; Morgan, J.S.; Price, P.; Tonry, J.; Wainscoat, R.

Abstract

We use the WISE-2MASS infrared galaxy catalogue matched with Pan-STARRS1 (PS1) galaxies to search for a supervoid in the direction of the cosmic microwave background (CMB) cold spot (CS). Our imaging catalogue has median redshift z ≃ 0.14, and we obtain photometric redshifts from PS1 optical colours to create a tomographic map of the galaxy distribution. The radial profile centred on the CS shows a large low-density region, extending over tens of degrees. Motivated by previous CMB results, we test for underdensities within two angular radii, 5°, and 15°. The counts in photometric redshift bins show significantly low densities at high detection significance, ≳5σ and ≳6σ, respectively, for the two fiducial radii. The line-of-sight position of the deepest region of the void is z ≃ 0.15–0.25. Our data, combined with an earlier measurement by Granett, Szapudi & Neyrinck, are consistent with a large Rvoid = (220 ± 50) h−1 Mpc supervoid with δm ≃ −0.14 ± 0.04 centred at z = 0.22 ± 0.03. Such a supervoid, constituting at least a ≃3.3σ fluctuation in a Gaussian distribution of the Λ cold dark matter model, is a plausible cause for the CS.

Citation

Szapudi, I., Kovács, A., Granett, B., Frei, Z., Silk, J., Burgett, W., …Wainscoat, R. (2015). Detection of a supervoid aligned with the cold spot of the cosmic microwave background. Monthly Notices of the Royal Astronomical Society, 450(1), 288-294. https://doi.org/10.1093/mnras/stv488

• Journal Article Type: Article
• Acceptance Date: Mar 4, 2015
• Online Publication Date: Apr 16, 2015
• Publication Date: Jun 11, 2015
• Deposit Date: Aug 3, 2015
• Publicly Available Date: Sep 4, 2015
• 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: 450
• Issue: 1
• Pages: 288-294
• DOI: https://doi.org/10.1093/mnras/stv488
• Keywords: Surveys, Cosmic background radiation, Cosmology: observations, Large-scale structure of Universe.
• Public URL: https://durham-repository.worktribe.com/output/1424621