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

Szapudi, István and Kovács, András and Granett, Benjamin R. and Frei, Zsolt and Silk, Joseph. (2015) Detection of a supervoid aligned with the cold spot of the cosmic microwave background. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 450 (1). pp. 288-294. ISSN 0035-8711

Preview

Text 1405.1566.pdf Available under License Creative Commons Attribution. Download (483kB) | Preview

Abstract

We use the WISE-2MASS infrared galaxy catalog matched with Pan-STARRS1 (PS1) galaxies to search for a supervoid in the direction of the Cosmic Microwave Back- ground Cold Spot. Our imaging catalog 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 Cold Spot shows a large low density region, extending over 10’s of degrees. Motivated by previous Cosmic Mi- crowave Background 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 et al. (2010), are consistent with a large Rvoid = (220 ± 50)h−1Mpc supervoid with δm ≃ −0.14 ± 0.04 centered at z = 0.22 ± 0.03. Such a supervoid, constituting at least a ≃ 3.3σ fluctuation in a Gaussian distribution of the ΛCDM model, is a plausible cause for the Cold Spot.

Actions (login required)

Edit Item