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

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 the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) 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 $\sim 7$) to derive constraints on cosmological parameters ($H_0=70.82_{-5.01}^{+4.94}$, ${\mathrm{\Omega }}_{\mathrm{m}}=0.290_{-0.068}^{+0.092}$, $w_0=-1.038_{-0.437}^{+0.245}$) and the average optical depth of the galaxy sample ($\lg \bar{\tau }=-4.24\pm 0.10$). 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 $H_0$–${\mathrm{\Omega }}_{\mathrm{m}}$, $H_0$–$w_0$ and ${\mathrm{\Omega }}_{\mathrm{m}}$–$w_0$ contours, respectively. For the first time, we demonstrate the complementary applicability of the kSZ effect in constraining cosmological parameters from real observational data.