The galaxy-formation origin of lensing-is-low
Showing how assembly bias, satellite segregation, and baryonic effects combine to explain the discrepancy.
Galaxy–halo connection · Lensing-is-low
The lensing-is-low problem
Why do models fitted to massive-galaxy clustering overpredict galaxy–galaxy lensing? My work traces the discrepancy to missing galaxy-formation physics rather than a failure of ΛCDM.
Standard galaxy–halo models can overpredict the lensing around massive galaxies by roughly 30 percent. Hydrodynamical simulations show that assembly bias, satellite segregation, and baryonic changes to the matter distribution all push the prediction in the same direction.
I helped show that these effects jointly explain the amplitude and scale dependence of lensing-is-low. Flexible SHAMe models can then fit clustering and lensing consistently, turning the discrepancy into a test of galaxy modelling rather than direct evidence for an anomalously low matter-clustering amplitude.
Selected work
From discrepancy to explanation
Simultaneous clustering and lensing with SHAMe
Validating a compact empirical model against TNG300 from quasi-linear to deeply nonlinear scales.
Consistent clustering and lensing of BOSS galaxies
Fitting both observables in Planck and low-S8 cosmologies without an artificial lensing discrepancy.