报告题目：The Massive Stellar Population of W49: a Spectroscopic Survey

　　报 告 人：Shiwei Wu （Max Planck Institute for Astronomy）

　　报告摘要：As a part of LOBSTAR project (Luci OBservations of STARburst regions) which aims at understanding the stellar content of young star-forming regions, I present our first result on the high-mass stellar content of W49. Near-infrared imaging observations are obtained with LUCI at the Large Binocular Telescope (LBT) and SOFI of New Technology Telescope(NTT). The K-band spectra (ISAAC/VLT) of the candidate massive stars provide us with more reliable spectral types than photometry alone. Four massive stars are identified as O3V-O5V stars while indications for an O2If-O3If star are found for a possible very massive star. After spectroscopic classification (and applying the proper extinction law), the objects can be placed in a Hertzsprung–Russell diagram. With comparison to stellar evolution models, the age of the cluster is estimated as lower than 2Myrs and the mass of the massive stars are calculated.　　

　　时    间：2014年4月29日星期二 上午10:00

　　地    点：（北京西路2号）紫台大楼619会议室

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