Testing the H0 and ?8 tensions with galaxy surveys and large-scale structure

Alex Krolewski (University of Waterloo)

November 30, -0001

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Abstract: The Lambda-CDM model has been incredibly successful at describing cosmological observations, but recent tensions could be hints that we require a new standard cosmological model. In this talk I will describe two research programs testing cosmological tensions. First, we measured the growth of structure and late-time amplitude of matter fluctuations (S8) by combining the unWISE catalog of 500 million infrared galaxies across the full sky with CMB lensing. unWISE galaxies and ACT + Planck CMB lensing measure S8= 0.810 ± 0.015, higher than the value of S8 preferred by cosmic shear and fully consistent with the amplitude inferred from the primary CMB. The unWISE catalog has also enabled a wealth of science in tandem with the cosmic infrared background and other CMB secondary anisotropies, and will continue to improve into the future with deeper WISE imaging and better characterization of its redshift distribution. Second, we introduce a new method for constraining the Hubble parameter with large-scale structure independent of the CMB and the comoving sound horizon. We isolate the amplitude of the baryonic feature in the observed galaxy power spectrum and use it to measure the baryon fraction ?b/?m. In combination with the BBN measurement of ?bh2 and measurements of ?m from the Alcock-Paczynski effect, we can measure H0 = 67.1+6.3-5.3 km/s/Mpc with BOSS. The full Euclid and DESI surveys offer an order of magnitude more volume than BOSS and can constrain H0 to ~1.2 km/s/Mpc precision with this method. Finally, I will conclude by discussing the future of these programs with the massive galaxy samples expected from ongoing and near-future surveys.