Evidence of Quasi-linear Super-structures in the Cosmic Microwave Background and Galaxy Distribution
Abstract
Recent measurements of hot and cold spots on the cosmic microwave background (CMB) sky suggest the presence of super-structures on (>100 h -1 Mpc) scales. We develop a new formalism to estimate the expected amplitude of temperature fluctuations due to the integrated Sachs-Wolfe (ISW) effect from prominent quasi-linear structures. Applying the developed tools to the observed ISW signals from voids and clusters in catalogs of galaxies at redshifts z < 1, we find that they indeed imply a presence of quasi-linear super-structures with a comoving radius of 100 ~ 300 h -1 Mpc and a density contrast |δ| ~ O(0.1). We also find that the observed ISW signals are at odds with the concordant Λ cold dark matter model that predicts Gaussian primordial perturbations at gsim3σ level. We confirm that the mean temperature around the CMB cold spot in the southern Galactic hemisphere filtered by a compensating top-hat filter deviates from the mean value at ~3σ level, implying that a quasi-linear supervoid or an underdensity region surrounded by a massive wall may reside at low redshifts z < 0.3 and the actual angular size (16°-17°) may be larger than the apparent size (4°-10°) discussed in literature. Possible solutions are briefly discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2010
- DOI:
- 10.1088/0004-637X/724/1/12
- arXiv:
- arXiv:1005.4250
- Bibcode:
- 2010ApJ...724...12I
- Keywords:
-
- cosmic background radiation;
- large-scale structure of universe;
- Astrophysics - Cosmology and Extragalactic Astrophysics;
- General Relativity and Quantum Cosmology
- E-Print:
- 34 pages, 13 figures, a version accepted for publication in ApJ. A plot of non-linear PDF (Figure 7) is added. Error bars are added in figure 8