The CMB in a Swiss-Cheese universe.

by Mr Wessel Valkenburg (LAPTH, Annecy)

Wednesday 27 May 2009, 11:00 → 12:00 Europe/Zurich

1/1-025 (CERN)

In the Swiss-Cheese universe, the apparent acceleration is explained as an artefact of gravitational lensing by voids. In this model, the universe is saturated with many voids and structures, hence the name. First I will explain and motivate this model, and show how a toy-model description gives a proof of concept. It has been shown that in this toy-model, the lensing effect disappears when the observer averages over all directions. It is not clear whether this is a consequence of the perfectly symmetric toy-model or not. However, I will show that on top of that, the highly non-linear structures necessary for this model, inevitably give a significant imprint on the CMB by means of the Rees-Sciama effect. This rules out most of parameter space that was considered up till now, and leaves open only few options for this model.

References:

• "On cosmological observables in a swiss-cheese universe", by Valerio Marra, Edward W. Kolb, Sabino Matarrese, Antonio Riotto [arXiv:0708.3622]
• "Luminosity distance in "Swiss cheese" cosmology with randomized voids: I. Single void size", by R. Ali Vanderveld, Eanna E. Flanagan, Ira Wasserman [arXiv:0808.1080]
• "Swiss Cheese and a Cheesy CMB", by Wessel Valkenburg [arXiv:0902.4698]