The WMAP Cold Spot as a Large Void: Impact on the CMB Power Spectrum and Bispectrum

by Dr Alessio NOTARI (CERN)

Wednesday 1 Oct 2008, 11:00 → 12:00 Europe/Zurich

1/1-025 (CERN)

Recent measurements of the CMB sky have revealed the existence of an unusually large cold region ("the Cold Spot"), with a significance of about 1%. If this feature is not just an unusual random fluctuation, it could be explained by a huge underdense structure along our line of sight. We will discuss the implications of such an hypothetical object on the global average statistical predictions for the CMB. In particular we will consider its imprint on the temperature power spectrum and on the bispectrum. This happens via two effects: the redshift of photons travelling across such a region (Rees-Sciama effect) and the lensing of primordial fluctuations by such a structure.

References:

• The non-gaussian cold spot in the 3-year wmap data, by Marcos Cruz, L. Cayon, E. Martinez-Gonzalez, P. Vielva & J. Jin, Published in Astrophys.J.655:11-20 (2007), e-Print: astro-ph/0603859
• The Cold Spot as a Large Void: Rees-Sciama effect on CMB Power Spectrum and Bispectrum, by Isabella Masina & Alessio Notari, e-Print: arXiv:0808.1811