Speaker:韦成亮（中国科学院紫金山天文台）/ Chengliang Wei (Purple Mountain Observatory)

Venue:Gewu 4410

Time:12:30 PM, Wednesday, 12nd December, 2018

Abstract:

The intrinsic alignment of galaxies is an important systematic effect in weak lensing surveys, which can affect the derived cosmological parameters. One direct way to distinguish different alignment models and quantify their effects on the measurement is to produce mock weak lensing surveys. In this talk, I will introduce our recent work on exploring galaxy intrinsic alignment with a mock catalogue produced by a combination of the full-sky ray-tracing simulation and the semi-analytical model of galaxy formation. Using the mock galaxy images, we compared the predicted tomographic shear correlations to the results of the Kilo-Degree Survey (KiDS), Deep Lens Survey (DLS) and Dark Energy Survey (DES). Our results favor a random alignment model for the satellite galaxies and explain the origin of the detected positive GI term in the weak-lensing surveys. We conclude that in future analyses, the GI model must include the dependence on galaxy types in more detail.

Personal Information:

韦成亮，博士毕业于紫金山天文台天体物理专业，现就职于中科院紫金山天文台星系宇宙学及暗物质研究团组。博士期间，基于球面光线追踪方法完成了高精度的包含星系分布和暗物质分布自洽的引力透镜成像模拟。