报告人：Prof. Martin C. Smith (SHAO)

时间：2016年4月19日下午4：00

地点：东区理化大楼18层天文台报告厅

报告摘要： For millennia we have measured the positions of stars in the heavens, leading to profound advances in our understanding of the universe. We are on the cusp of another such era, as new surveys are performing astrometry to unprecedented precision. These surveys have proved to be a fabulously rich resource for learning about our own Galaxy. I will discuss some important results from proper motion surveys, showing how the kinematics of stars around us can tell us much about both the disc and the halo of the Milky Way. Exploiting the Sloan Digital Sky Survey Stripe 82 catalogue we have uncovered relics of accretion in halo, probed the shape of the dark matter distribution, and constrained the mass profile of the disc. Datasets such as the SDSS Stripe 82 catalogue are a crucial test-bed for future studies. Excitement in this field is now building due to the recent launch of the Gaia space astrometry satellite. This European-led mission will measure the positions and velocities of stars to previously unimaginable precision, for the first time enabling ages to be measured for huge numbers of stars. LAMOST has a crucial role to play, providing radial velocities and chemistry for millions of Gaia stars. With the first data release due later this year, the Gaia-era is almost upon us. By driving progress in understanding our own Galaxy, such surveys will revolutionise our knowledge how galaxies form and evolve in the universe.