Clusters of galaxies trace the most non-linear peaks in the cosmic density field. The weak gravitational lensing of background galaxies by clusters can allow us to infer their masses. However, galaxies associated with the local environment of the cluster can also be intrinsically aligned due to the local tidal gradient, contaminating any cosmology derived from the lensing signal. In this talk, I will present our measurement of the IA signal in DES Y1. This is an important demonstration of the ability of large photometric data sets like DES to provide direct constraints on the intrinsic alignment of galaxies within clusters. These measurements can inform improvements to small-scale modeling and simulation of the intrinsic alignment of galaxies to help improve the separation of the intrinsic alignment signal in weak lensing studies. Finally, I will briefly touch on the topic of using IA to calibrate projection effect in cluster cosmology.
BIO
Conghao Zhou is a graduate student at University of California, Santa Cruz. He received his Bachelor degree at Duke University in 2020. His research interests involve dark matter, gravitational lensing, galaxy clusters and so on.
