The cold spot as a large void: Rees-Sciama effect on CMB power spectrum and bispectrum
- CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)
The detection of a ''Cold Spot'' in the CMB sky could be explained by the presence of an anomalously large spherical underdense region (with radius of a few hundreds Mpc/h) located between us and the Last Scattering Surface. Modeling such an underdensity with an LTB metric, we investigate whether it could produce significant signals on the CMB power spectrum and bispectrum, via the Rees-Sciama effect. We find that this leads to a bump on the power spectrum, that corresponds to an O(5%-25%); correction at multipoles 5 {<=} l {<=} 50; in the cosmological fits, this would modify the {chi}{sup 2} by an amount of order unity. We also find that the signal should be visible in the bispectrum coefficients with a signal-to-noise S/N {approx_equal} O(1-10), localized at 10 {<=} l {<=} 40. Such a signal would lead to an overestimation of the primordial f{sub NL} by an amount {Delta}f{sub NL} {approx_equal} 1 for WMAP and by {Delta}f{sub NL} {approx_equal} 0.1 for Planck.
- OSTI ID:
- 22156904
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2009, Issue 02; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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