Cosmic troublemakers: the Cold Spot, the Eridanus Supervoid, and the Great Walls

Nov 29, 2015
12 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 462 (2016) 2, 1882-1893
  • Published: Oct 21, 2016
e-Print:
Report number:
  • IFT-UAM-CSIC-15-132

Citations per year

201520172019202120230246810
Abstract: (Oxford University Press)
The alignment of the CMB Cold Spot and the Eridanus supervoid suggests a physical connection between these two relatively rare objects. We use galaxy catalogues with photometric (2MPZ) and spectroscopic (6dF) redshift measurements, supplemented by low-redshift compilations of cosmic voids, in order to improve the 3D mapping of the matter density in the Eridanus constellation. We find evidence for a supervoid with a significant elongation in the line of sight, effectively spanning the total redshift range z < 0.3. Our tomographic imaging reveals important substructure in the Eridanus supervoid, with a potential interpretation of a long, fully connected system of voids. We improve the analysis by extending the line-of-sight measurements into the antipodal direction that interestingly crosses the Northern Local Supervoid at the lowest redshifts. Then it intersects very rich superclusters like Hercules and Corona Borealis, in the region of the Coma and Sloan Great Walls, as a possible compensation for the large-scale matter deficit of Eridanus. We find that large-scale structure measurements are consistent with a central matter underdensity δ_0 ≈ −0.25, projected transverse radius r0195r_{0}^{\perp }\approx 195 Mpc h^−1 with an extra deepening in the centre, and line-of-sight radius r0500r_{0}^{\parallel }\approx 500 Mpc h^−1, i.e. an ellipsoidal supervoid. The expected integrated Sachs–Wolfe imprint of such an elongated supervoid is at the ΔT_ISW ≈ −40 μK level, thus inappropriate to accounting for the Cold Spot pattern in the CMB.
Note:
  • 13 pages, 9 figures. Accepted by MNRAS in this form
  • surveys
  • cosmic background radiation
  • cosmology: observations
  • large-scale structure of Universe