The galaxy intrinsic alignment (IA) is both a major source of systematic errors in weak lensing cosmology, and an emerging tracer of the large scale structure of the Universe. Separating IA from weak lensing (cosmic shear) usually requires a fiducial IA model and is thus IA model-dependent. We have proposed a self-calibration method to avoid this model dependency. Recently we applied it to KIDS450/KV450 and DECaLS DR3. We detected IA at ~20-sigma, without any assumptions of IA. We also detected its dependence on redshift and galaxy type.
BIO
Pengjie Zhang is a professor at the Department of Astronomy and an associate fellow at the Tsung-Dao Lee institute, Shanghai Jiao Tong University. He works on the the large scale structure of the universe and its applications in probing fundamental cosmological physics.
Host: Dandan Xu
