Title:  Quantifying Dark Gas

Speaker: Di Li (NAOC)  

Time & Place: Thursday, 3:00pm, May 8th, Lecture Hall, 3rd floor

Abstract:  The recent decade is seeing a convergence of evidences, which hint at the existence of dark gas, namely, a substantial fraction of gaseous ISM previous undetected. The observations from space observatories, such as IRAS, Planck, EGRET, and Herschel, bring to the forefront the issue of how much such dark gas there is and what exactly it is. I will introduce our plan to systematically quantify dark gas in the Milky Way through absorption studies. We will utilize all major ground-based telescopes, such as Arecibo, JVLA, ATCA, and ALMA.
The Five-hundred-meter Aperture Spherical radio Telescope (FAST) will obtain first light toward the end of 2016. It is particularly suitable for sensitivity limited studies. Here I will also report the status of the FAST project, and particularly, how it will shed light on the issue of dark gas.

Biog: Dr. Li has lead many research programs, including projects at Arecibo, FCRAO, SWAS, Spitzer, Herschel, and SOFIA. He pioneered several observing techniques, including HI narrow self-absorption (HINSA) technique and a new inversion solution to the dust temperature distribution. These techniques lead to important measurements of star forming regions, such as the formation time scale. He is the key member of the team who first discovered molecular oxygen in space and then confirmed it with Herschel. His works have been highlighted on Nature magazine as one of the Astronomy highlights of 2010 and have been cited by numerous review articles. He is now leading the science preparation and international collaboration of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) project as the PI of a 973 project “The Frontiers in Radio Astronomy and FAST Early Sciences”. Li servers on numerous international committees, including the Australian Telescope National Facilities (ATNF) Steering Committee and the Stratospheric Observatory for Infrared Astronomy (SOFIA) user group.