Time: 14:00
　  Date: Nov. 8th. Thursday
　  Room: 1714

　  Presenters: Martin C. Smith from SHAO & Mathew Molloy from KIAA/PKU

　  Topic:

 Martin C. Smith, SHAO

 "A Lack of Dark Matter in the Solar Neighbourhood?"

 Matthew Molloy, KIAA/PKU

 "Kinematic Signatures of Galaxy Bars"

Abstract:

Here's Martine's abstract

"Large surveys such as the Sloan Digital Sky Survey (SDSS) are enabling detailed studies to be made of the properties of the Milky Way, analysing the spatial distribution of stars as well as their kinematics. We have constructed a high-precision catalogue of disk stars using data from SDSS and use these stars to probe the global properties of the Milky Way disk, employing Jeans analysis to provide a simple model of the potential close to the disk. Our model is in excellent agreement with others in the literature and provides an indication that the disk, rather than the halo, dominates the local circular speed. We discuss the impact of these results on the search for dark matter in the solar neighbourhood."

And Matthew's Abstract:

"Recent measurements of galacto-centric radial velocities of red clump stars show a bifurcation in the distribution between a distance of 10-11 kpc (Liu et al., 2012). We investigate the kinematic structures of the N-body simulation by Shen et al., (2010) who shows that the dynamical and photometric properties of the Galactic bulge can be replicated by a pure disc galaxy that naturally and self consistently develops a bar. The simulation data show a striking similarity (i.e., a bifurcation in the velocity distribution) to the observed kinematics in the Solar neighbourhood."