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Astro Seminar

Large-scale structure cosmology with quasars

Speaker: Kate Storey-Fisher (Donostia International Physics Center)
Date: Wednesday 28 February 2024
Time: 14:00
Venue: N3.28/Zoom

Quasars can be seen out to high redshifts and trace the matter distribution at large scales. Maps of quasars allow for precise estimates of cosmological parameters, as well as tests of some of the fundamental assumptions of the standard cosmological model. I will present a new all-sky catalog of quasars for cosmology, Quaia, which is based on data from Gaia and unWISE and samples the largest comoving volume of any existing quasar sample. I will discuss the construction of the catalog and share the results of cosmological analyses, including cross-correlations with CMB lensing. I will highlight our measurement of the kinematic dipole with Quaia; we find a dipole amplitude in mild tension with the CMB expectation, but show that this is very dependent on sample and fitting choices.