邀请人 (Invited by): 李霄栋

时间 (Time): 星期五，2023/7/7-10：30-12：00

地点 (Location): 珠海校区天琴中心3416会议室

摘要 (Abstract): 

LCDM is the standard model of modern cosmology with two dark components, dark matter and dark energy. The nature of dark energy and the dark matter structure growth rate can be probed via the large-scale structure (LSS). For this purpose, we observe millions of spectra of galaxies and quasars (QSO) from spectroscopic galaxy surveys. Meanwhile, high-resolution N-body simulations can reproduce the theoretically predicted LSS and provide properties of dark matter haloes. The relation between galaxy/quasar-haloes is highly non-linear and subject to the local environment and is also crucial for accurate cosmological measurements.

SubHalo Abundance Matching (SHAM) is an empirical method to assign galaxies to dark matter haloes from N-body simulations. However, its classical version only works for luminous red galaxies (LRGs, most of which are quiescent). In this talk, we introduce an inclusive SHAM for LRGs,  emission line galaxies (ELGs, mostly star-forming) and QSOs, accounting for the massive (sub)halo incompleteness, the redshift uncertainty and the satellite fraction. Its model galaxies reproduce the clustering of observation on scales of 5-30Mpc/h and at 0.4<z<3.5 and a consistent halo occupation results with HODs. The algorithm can be easily transferred to a multi-tracer SHAM for cosmological measurement and cosmic web studies and is important for neutrino mass and modified gravity studies by removing the redshift uncertainty bias.

主讲人简介 (Speaker's CV): 

Jiaxi Yu is a current Ph.D. candidate at the Laboratory of Astrophysics at EPFL, Lausanne, Switzerland. Her research interests are observational cosmology, large-scale structure of the universe. She studies the galaxy-halo connection of galaxies and quasars from spectroscopic surveys like SDSS and DESI. She is also interested in quantifying the observational systematics on those surveys for the two-point correlation function that is key for cosmological measurements like Baryonic Acoustic Oscillation and Redshift Space Distortion.