Résumé / Abstract Journal-club_Univers

Journal-club Univers / Journal-club Universe

« Probing large-scale structures with quasars »

Pauline Zarrouk
Dept. Physics, Univ. Durham (Durham, Royaume-Uni)

Since the fall 2014, the SDSS-IV eBOSS multi-object spectrograph has undertaken a survey of quasars in the almost unexplored redshift range 0.8 < z < 2.2 with the key science goal to complement the constraints on dark energy and extend the test of general relativity at higher redshifts by using quasars as direct tracers of the matter field.
In this journal club, I will present the cosmological results of the two-year sample of eBOSS quasars, which includes the first detection of the Baryon Acoustic Oscillations (BAO) feature in the intermediate redshift range 1 < z < 2 (Ata et al. 2017, arXiv:1705.06373) and the full-shape analysis in configuration space (Zarrouk et al. 2018; arXiv:1801.03062) using Redshift Space Distortions (RSD). This study is a first use of eBOSS quasars as tracers of the matter field and will be included in the analysis of the final eBOSS sample at the end of 2019 with an expected improvement on the statistical precision of a factor 2. I will also describe the challenges we need to face for the analysis of the final eBOSS samples and for the preparation of DESI, the next spectroscopic survey that will start taking data in 2020 with the main goal to improve the cosmological constraints by an order of magnitude with respect to current measurements.
Eventually, I will briefly introduce a new method to improve the BAO measurement in a sparse spectroscopic sample like the eBOSS quasars one by making advantage of cross-correlations with a dense photometric sample following the methodology in Patej & Eisenstein (2017, arXiv:1709.03514) with the goal to apply it to eBOSS quasars and a photometric sample of emission line galaxies from Legacy Surveys.

mardi 12 mars 2019 - 11:15
Salle Planck, Institut d'Astrophysique
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