Speaker
Description
Recently, velocity-weighted stacked kSZ measurements around galaxy groups have
become feasible, offering a competitive way to probe the gas distribution around
groups. These new measurements appear to imply very strong baryonic feedback,
somewhat in tension with previous X-ray observations. However, it is still unclear
whether the theoretical modelling used so far is sufficiently detailed to describe the
signal accurately. In this talk, I will present a comprehensive analysis of realistic
mock stacked-kSZ measurements based on hydrodynamic simulations that include
non-linear physics and complex astrophysical processes. By separating the signal
into its different components and isolating the processes that affect the density and
velocity, I will identify the physical mechanisms that contribute to the kSZ signal and
therefore need to be included in a successful model. In particular, I will discuss the
impact of satellites, non-linear effects in the velocity field and velocity decorrelation,
the performance of velocity reconstruction, and baryonic effects on density and
velocity fields. Accounting for these effects will be essential, given the precision of
upcoming measurements, to extract reliable information about the gas distribution
and assess the strength of baryonic feedback in the Universe.