Constraining modified gravity with Cosmic voids

Stage numéro : M2-1920-RE-02
Laboratoire :Centre de Physique des Particules de Marseille Case 902
 163 avenue de Luminy - 13288 Marseille Cedex 9
Directeur :Cristinel Diaconu - 04.91.82.72.01 - diaconu@cppm.in2p3.fr
Correspondant :William Gillard - 04.91.82.72.67 - gillard@cppm.in2p3.fr
Groupe d'accueil :Renoir
Chef de groupe :Dominique Fouchez - 04.91.82.72.49 - fouchez@cppm.in2p3.fr
Responsable de stage :Stéphanie ESCOFFIER - 04 91 82 76 64 - escoffier@cppm.in2p3.fr

Thématique : Cosmologie observationnelle

<bold>Scientific context of the project</bold>

Voids are very low-density environments in the large-scale distribution of matter in the Universe. As they are nearly devoid of matter, voids constitute a promising new probe for testing cosmological models and theories of gravity (Baker et al. 2018; Cai 2018; Hamaus et al. 2016).

We propose here to look for cross-correlation between CMB and voids. With the imminent massive influx of cosmological data like the DESI ground-based dark energy experiment, the number of observed objects is expected to be at least one order of magnitude. Indeed, the DESI instrument will conduct a five-year survey designed to cover 14,000 deg2 and to map the large-scale structure of the Universe from redshift 0 to 3.5 by measuring 34 million redshifts (Aghamousa et al. 2016). The expected number of voids is several tens of thousands. The DESI project will begin the survey in June 2020 after 4 months of Survey Validation. At CPPM we were involved in the construction and testing of the 10 DESI spectrometers. We are full member of DESI with guaranteed access to the DESI private data.

<bold>Description of the internship work </bold>

The aim of the internship is to cross-correlate Planck CMB maps with cosmic voids from eBOSS DR16 data. A part of the work will consist of optimizing the signal from voids.