报告题目：Accurate measurement of the Milky Way's mass in cosmological context

报 告  人：景益鹏 院士 上海交通大学

报告时间：2019-11-28 15:00:00

报告地点：天文楼212报告厅

摘要：

I will briefly review recent development of observational cosmology, and

outline the importance of determining the mass of the Milky Way. Then I will

present the current status of the Milky Way mass measurement and discuss the

main uncertainties and shortcomings associated with previous methods.  I will

then present our new method in order to overcome most of the drawbacks. The 6D

phase space distribution function of satellites is constructed from

cosmological simulations based on the similarity implied by the NFW profile.

Within the Bayesian statistical framework, we can not only infer the halo mass

efficiently, but also handle various observational effects including the

selection function, incomplete information (e.g., lack of proper motion), and

measurement errors in a rigorous and straightforward manner. Through mock

tests, we show that this method is accurate and unbiased, and superior to

methods solely based on Jeans theorem. We also demonstrate the satellite

galaxies are better tracers than stars in general. Applying our method to the

recent GAIA observations has yielded the most accurate determination of the

Milky Way mass.  While the important application of our method is to measure

the Milky Way halo mass, it can be extended to any other galaxies or clusters

whose member satellites can be reliably identified.