Sunday, 25 September 2022

Astronomy Colloquium (8.6/2022):Impacts of galaxy intrinsic alignments on weak lensing peak statistics

06.08.2022 2:00 pm - 3:00 pm



Title:Impacts of galaxy intrinsic alignments on weak lensing peak statistics
Speaker:Zuhui Fan(范祖辉)
Abstract:With the completion of the Stage III weak lensing (WL) surveys, we are entering the Stage IV era. The upcoming surveys target at accurately measuring light distributions for over a billion far-way galaxies for high-precision WL cosmological studies. With a dramatic decrease of statistical uncertainties, systematic effects are becoming the dominant part in the error budget, and need to be carefully investigated and mitigated. In this talk, I will present our studies about the impacts of galaxy intrinsic alignments (IA) on WL peak statistics using simulations with semi-analytical galaxy formation. Our results show that WL peaks, particularly high peak counts, are sensitive to satellite IA due to the inclusion of satellite galaxies in shear samples. The IA contribution to the variance of galaxy shape noise also plays a role. With the IA effects taken into account properly in the peak modeling, we will be able to mitigate the IA induced bias in cosmological constraints while simultaneously deriving the astrophysical information about satellite IA. 
Zuhui Fan received her Ph.D. from University of Washington in Seattle, U.S.A., and was a visiting scientist and a postdoc fellow at University of Chicago and Taiwan University/ASIAA, Taiwan. From 2002 to 2018, she was a professor at Department of Astronomy, School of Physics, Peking University. She is now a professor at South-Western Institute for Astronomy Research, Yunnan Univ.. Her research interest is in cosmology, particularly in weak lensing studies.
Time:14:00-15:00PM, 8/June, Wednesday
Meeting ID: 831 4360 9634
Passcode: 436377
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