报告题目：Kinetic Temperatures of Molecular Gas: The Galactic Center Region

　　摘    要：The Galactic center (GC) region is the closest galaxy core. It is characterized by a high concentration of molecular gas located in the innermost few hundred parsec of the Milky Way, the Central Molecular Zone (CMZ), and by extreme conditions like high mass densities, large velocity dispersions, strong tidal forces, and strong magnetic fields. Therefore it is a unique laboratory for studying molecular gas in an environment that is quite different from that of the Milky Way’s disk. For a general understanding of the physics involved in galactic cores, measurements of basic physical parameters, such as molecular gas density and gas kinetic temperature, are indispensable.
　　          We have mapped the inner 300 pc of the CMZ in the temperature sensitive J=3-2 para-formaldyde (p-H2CO) transitions. We use the 321-220/303-202 line ratio to determine the gas temperature in an environment with typical densities of 104 to 105 cm-3. The data cube contains data with 30 arcsec and 1 km/s resolution. Gas temperatures range from about 60 to >100 K. The high temperatures are obtained towards Sgr B2, the 20 and 50 km/s clouds and the Brick. An upper limit to the cosmic ray ionization rate is derived. Gas and dust temperatures are being compared and the dominant heating mechanism is identified for the first time. 

　　报 告 人：Prof. Christian Henkel (Max-Planck-Institut für Radioastronomie，Germany)

　　报告人简介：Christian Henkel,著名天体物理学家，1977年获得德国波恩大学天体物理学博士学位，之后在美国加州大学伯克利分校和美国新泽西州贝尔实验室做博士后研究工作。1983年至今在马普射电所毫米波亚毫米波组任高级科学家。曾在ESO，ATNF，ESO-ALMA Group，Onsala 空间天文台等著名国际天文机构做访问学者。Henkel教授主要参与了SMT，APEX等望远镜的建设，以及利用德国100米望远镜计算基本物理常数等项目。他的研究兴趣十分广泛，研究领域涵盖了分子谱线，恒星形成，活动星系核，宇宙中的化学演化，基本物理常数测定，脉泽等。至今发表论文540余篇，总引用超过10400余次(根据ADS数据库)。Henkel教授在实测方面有丰富的经验，欢迎各位同事、同学积极与教授进行交流讨论。

　　报告时间：2015年7月8日（星期三） 下午16：00

　　报告地点：台本部110会议室

　　联 系 人：黄春苹 0991-3689050