Much ado about nothing - do we live in a void?

by Prof. Subir Sarkar (Oxford)

Wednesday 30 Jul 2008, 11:00 → 12:00 Europe/Zurich

1/1-025 (CERN)

It has been suggested that the inference of accelerated expansion from the SNe Ia Hubble diagram may be biased because we are located in a large underdense region which is expanding faster than the average. This may also account for the observed alignment of the low multipoles in the CMB. However such large voids are extremely unlikely according to the standard theory of structure formation matched to WMAP data. Nevertheless a number of them have recently been identified in the SDSS LRG survey in a search for the late ISW effect. We will discuss the implications of these findings, as well as other constraints on such voids from the lack of spectral distortions in the CMB spectrum. Suggested reading: "Constraints on large scale voids from WMAP-5 and SDSS" P. Hunt and S. Sarkar arXiv:0807.4508 "An Imprint of Super-Structures on the Microwave Background due to the Integrated Sachs-Wolfe Effect" B. Granett, M. Neyrinck, I. Szapudi arXiv:0805.3695 "Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae" S. Alexander, T. Biswas, A. Notari and D.Vaid, arXiv:0712.0370 "A Test of the Copernican Principle" R. Caldwell and A. Stebbins, arXiv:0711.3459 "Looking the void in the eyes - the kSZ effect in LTB models" J. Garcia-Bellido and T. Haugboelle, arXiv:0807.1326