Publication Date:
2015-04-22
Description:
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, 5 and 6, 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 R void = (220 ± 50) h –1 Mpc supervoid with m ~= –0.14 ± 0.04 centred at z = 0.22 ± 0.03. Such a supervoid, constituting at least a ~=3.3 fluctuation in a Gaussian distribution of the cold dark matter model, is a plausible cause for the CS.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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