报告题目：New views on the Andromeda galaxy M31

　　报 告 人：David Valls-Gabaud (Observatoire de Paris, CNRS, IHEP, NAOC)

　　报告摘要：The detailed analysis of colour-magnitude diagrams obtained at the Canada-France-Hawaii telescope has revealed hitherto unknown properties of the nearest spiral galaxy, M31. The recent star formation history in the disc shows that M31 is a starving galaxy in the so-called green valley. Time-domain series carried out over two years provide the first comprehensive variability inventory of this galaxy. Hubble Space Telescope follow-up observations of some of the Cepheids discovered have led to a determination of its distance with an error of 3%, and likewise for the Hubble constant, by-passing the uncertainties in the calibration of the Magellanic Clouds. The analysis of the halo fields has revealed not only many substructures at faint surface brightness levels, but a wealth of information on new satellites, globular clusters, stellar streams, and the structure of the halo. Over half of the satellites of M31 appear to lie in a vast disc, which is rotating around the galaxy, yielding stringent constraints on the accretion mechanisms which lead to the formation of galaxies.

　　时    间：2014年3月5日周三 上午10:00

　　地    点：紫台大楼619会议室

　　联 系 人：李月月（83332162）

欢迎大家积极参加！

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