First Cosmological Constraints from the Joint Analysis of Galaxy Clustering and the Kinetic Sunyaev–Zel’dovich Effect

Abstract We perform the first joint analysis of galaxy clustering (GC) and the kinetic Sunyaev–Zel’dovich (kSZ) effect to simultaneously constrain cosmological and astrophysical parameters in this work, utilizing a combination of an Atacama Cosmology Telescope Data Release 6 map and the Constant Stellar Mass (CMASS) galaxy sample. As a complementary probe to the galaxy density power spectrum, we incorporate the pairwise kSZ power spectrum detected with a high signal-to-noise ratio (S/N ∼ 7) to derive constraints on cosmological parameters ( H 0 = 70.8 2 − 5.01 + 4.94 , Ω m = 0.29 0 − 0.068 + 0.092 , w 0 = − 1.03 8 − 0.437 + 0.245 ) and the average optical depth of the galaxy sample ( lg τ ¯ = − 4.24 ± 0.10 ). Compared to the GC-only analysis, the joint analysis yields tighter constraints on these cosmological parameters: the Figures of Merit improve by 20.5%, 19.7%, and 10.0% for the H 0 –Ω m , H 0 – w 0 , and Ω m – w 0 contours, respectively. For the first time, we demonstrate the complementary applicability of the kSZ effect in constraining cosmological parameters from real observational data.