报告题目：Molecular gas in HI-rich UDGs

　　报告人：王均智 研究员（中国科学院上海天文台）

　　报告人简介：Junzhi Wang is currently a research Professor at radio division of Shanghai Astronomical observatory (SHAO). He got his PhD degree in Astronomy at PKU in 2005. During 2002-2004, he was an SAO pre-doc working in the sub-millimeter Array group. He was then a postdoc at Purple Mountain Observatory and an associate professor of astronomy in NJU until June 2013. His research interests are star formation and ISM in nearby galaxies and the Milky Way, AGN feedback, and Mega-masers, using radio and (sub-)millimeter facilities in the world, including IRAM 30 meter, Effelsberg, JVLA, NOEMA, SMA, and the ALMA.

　　报告摘要：We present CO observations toward a sample of six HI-rich Ultra-diffuse galaxies (UDGs) as well as one UDG (VLSB-A) in the Virgo Cluster with the IRAM 30-m telescope. CO J=1-0 is marginally detected at 4σ level in AGC122966, as the first detection of CO emission in UDGs. We estimate upper limits of molecular mass in other galaxies from the non-detection of CO lines. These upper limits and the marginal CO detection in AGC122966 indicate low mass ratios between molecular and atomic gas masses. With the star formation efficiency derived from the molecular gas, we suggest that the inefficiency of star formation in such HI-rich UDGs is likely caused by the low efficiency in converting molecules from atomic gas, instead of low efficiency in forming stars from molecular gas.

　　报告时间：2020年12月17日下午16:00

　　报告地点：紫台仙林园区5号楼316会议室

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