Disentangling the halo: joint model for measurements of the kinetic Sunyaev–Zeldovich effect and galaxy–galaxy lensing

ABSTRACT We present the first joint analysis of the kinetic Sunyaev–Zeldovich (kSZ) effect with galaxy–galaxy lensing (GGL) for CMASS galaxies in the Baryon Oscillation Spectroscopic Survey. We show these complementary probes can disentangle baryons from dark matter in the outskirts of galactic haloes by alleviating model degeneracies that are present when fitting to kSZ or GGL measurements alone. In our joint kSZ + GGL analysis we show that the baryon density profile is well constrained on scales from 0.3 to 50 Mpc$\,h^{-1}$. With our well-constrained profile of the baryon density, we provide direct comparisons to simulations. For our model we find an outer slope of the baryon distribution that is shallower than predicted by some hydrodynamical simulations, consistent with enhanced baryonic feedback. We also show that not including baryons in a model for GGL can shift halo mass estimates by $\sim 20~{{\ \rm per\ cent}}$ compared to a model that includes baryons and is jointly fit to kSZ + GGL measurements. Our modelling code GGL and kSZ (glasz) is publicly available at https://github.com/James11222/glasz.