报告摘要

A major uncertainty in the determination of the mass profile of the Milky

Way using stellar kinematics is the poorly determined anisotropy parameter,

beta = 1 - ( ( (sigma_theta)**2 + (sigma_phi)**2 ) / ( 2 * (sigma_r)**2 ),

where sigma_r is the Galactocentric radial velocity dispersion, and

sigma_theta and sigma_phi are the tangential components of the velocity

dispersion. We use a sample of over 22,000 Galactic halo K giant and blue

horizontal branch stars from the ground-based LAMOST and SDSS/SEGUE stellar

spectroscopic surveys, combined with proper motions from the space telescope

Gaia, to measure beta(r) over a wide range of Galactocentric distances r

from 4 to 100 kpc. We investigate the extent to which a much improved

knowledge of beta influences the determination of the Galactic mass profile

M(r) as a function of r.

报告人

Sarah A. Bird from NAOC

报告人介绍

Dr. Sarah A. Bird received her Ph.D. from the University of Turku in

Finland in 2014, upon which she began as a LAMOST Fellow at the Shanghai

Astronomical Observatory and later continued as a PIFI Postdoctoral Fellow.

In 2018 she moved to NAOC in Beijing with the Aliyun Fellowship.

Her research focuses on the stellar halos of the Milky Way and other

galaxies which she investigates using both observations and simulations.

地点

物理学院新楼the 4th floor

时间

25th September (Friday)，10 am

邀请人