报告题目：Constraints on Variations of Fundamental Constants from High Redshift Atomic and Molecular Emission and Absorption
报 告 人：Prof. Karl M. Menten (Max-Planck-Institut fuer Radioastronomie)
报告人简介：Karl Menten教授是国际上射电天文领域的知名专家，1992年获得哈佛-史密松天体物理中心的终身职位，1996年开始长期担任德国马普射电天文研究所的所长和波恩大学的荣誉教授等职，获得过国际上多项重要奖项和荣誉，包括射电天文领域最负盛名的Karl G. Jansky Lectureship，德国National Academy of Sciences的Elected ordinary member，英国Royal Astronomical Society的Elected Honorary Fellow等。Karl Menten教授的研究兴趣涉及射电天文的几乎所有相关课题，从银河系恒星形成、星际介质、旋臂结构到超大质量黑洞、AGN，以及高红移宇宙、引力透镜、CMB等，迄今发表正式论文500多篇，引用近2万次。
摘 要：The standard model of physics does not require the fundamental constants of nature (FCs) to be constant in space and time. In the past, quests to measure possible variations have mostly been performed with atomic and molecular hydrogen as well as metal absorption lines at (observer frame) optical wavelengths. At (sub)millimeter and radio wavelengths, in various cases dramatically different dependences of certain spectral lines’ wavelengths on FCs allow for extremely sensitive constancy tests. Farthest back in time, to 12.8 Gyr, reach our recent sensitive limits on a combination of the fine structure constant and the proton-to-electron mass ratio that we determined from sensitive measurements of emission from rotational CO and fine structure lines from atomic or ionized carbon toward high redshift (up to z = 6.4) quasar host galaxies. We shall briefly summarize these but shall concentrate on absorption line measurements, which are much more sensitive. At present, 5 (sub)mm- and/or radio-wavelength molecular line absorbers are known at cosmological distances, all at z < 0.9 and thus probing look back times up to about 7 Gyr. Three of these are the lensing galaxies of gravitational lens systems. Observations of numerous different molecules toward one of these systems not only deliver the tightest cosmological limits to date on variations of the proton-to-electron mass ratio, but also reveal a fascinating astrochemistry that is quite different from that of the Milky Way’s interstellar medium. We shall also provide an outlook on opportunities with the ALMA and the JVLA today and with the SKA in the future.
时间及地点：3月25日（周三）下午3点，天文楼212报告厅
