Astrophysical systematics in weak lensing

Current and upcoming large galaxy surveys will provide a wealth of cosmological information about our Universe. Weak lensing is one of the primary probes to uncover the nature of dark energy through its sensitivity to the growth of structure across cosmic time. However, a detailed understanding about systematic effects is required to make robust cosmological inferences from data. Besides shear calibration and photometric redshift systematics, intrinsic alignment and the effects of baryons on the observables constitute two major astrophysical systematics for weak lensing. In this talk, I will focus on discussing these two sources of astrophysical systematics. I will first introduce two methods to mitigate the effects of baryons for cosmic shear, and validate their performances for a future LSST-like survey under a variety of baryonic scenarios constructed from hydrodynamical simulations. In the second part of my talk, I will discuss the importance of intrinsic alignment, and present our measurements of intrinsic alignments of central and satellite galaxies in redMaPPer clusters.

Speaker: Hung-Jin Huang, CMU