Weak lensing combined with the kinetic Sunyaev Zel'dovich effect: A study of baryonic feedback
arxiv(2024)
摘要
Extracting precise cosmology from weak lensing surveys requires modelling the
non-linear matter power spectrum, which is suppressed at small scales due to
baryonic feedback processes. However, hydrodynamical galaxy formation
simulations make widely varying predictions for the amplitude and extent of
this effect. We use measurements of Dark Energy Survey Year 3 weak lensing (WL)
and Atacama Cosmology Telescope DR5 kinematic Sunyaev-Zel'dovich (kSZ) to
jointly constrain cosmological and astrophysical baryonic feedback parameters
using a flexible analytical model, `baryonification'. First, using WL only, we
compare the S_8 constraints using baryonification to a simulation-calibrated
halo model, a simulation-based emulator model and the approach of discarding WL
measurements on small angular scales. We find that model flexibility can shift
the value of S_8 and degrade the uncertainty. The kSZ provides additional
constraints on the astrophysical parameters and shifts S_8 to
S_8=0.823^+0.019_-0.020, a higher value than attained using the WL-only
analysis. We measure the suppression of the non-linear matter power spectrum
using WL + kSZ and constrain a mean feedback scenario that is more extreme than
the predictions from most hydrodynamical simulations. We constrain the baryon
fractions and the gas mass fractions and find them to be generally lower than
inferred from X-ray observations and simulation predictions. We conclude that
the WL + kSZ measurements provide a new and complementary benchmark for
building a coherent picture of the impact of gas around galaxies across
observations.
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