Detection of a supervoid aligned with the cold spot of the cosmic microwave background
/ Authors
I. Szapudi, A. Kov'acs, B. Granett, Z. Frei, J. Silk, W. Burgett, S. Cole, P. Draper, D. Farrow, N. Kaiser
and 6 more authors
E. Magnier, N. Metcalfe, J. Morgan, P. Price, J. Tonry, R. Wainscoat
/ 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.
Journal: Monthly Notices of the Royal Astronomical Society
DOI: 10.1093/mnras/stv488