Title:Interstellar Gas Dynamics and the FAST Telescope
Reporter：Prof. Carl E. Heiles
Time: Thursday 14:30 PM, Oct.11st
Location: Room 1522, Physics Building
Abstract：
Interstellar space is pervaded by interstellar gas, which is 92% hydrogen. It exists in five distinct phases: most of it is cold molecular gas and cool atomic gas having temperatures of a few Kelvin to a few hundred Kelvin, but there is also warm atomic gas and ionized gas at temperatures ranging up to 3 million Kelvin. This wide range of physical conditions occurs because of stars and their radiation. New stars form in the cold molecular gas, their starlight warms the gas, and their explosive demise produce rapidly expanding bubbles full of the hot ionized gas, bounded by shock fronts containing denser gas that rapidly cools to become molecular and then perpetuates the star-formation cycle. All of these dynamical actions are subject to the major forces: gravity, gas turbulence, magnetism, and cosmic rays. The FAST telescope will play a major role in mapping the kinematics of the atomic hydrogen using the 21-cm line and help us to understand the physical processes at work in interstellar space.
Prof. Carl E. Heiles introduction：
Prof. Carl E. Heiles received his Bachelor’s degree in engineering physics from Cornell University in 1962, and then received his Ph.D. in astrophysical sciences from Princeton University in 1966. He has worked at the University of California, Berkeley since, and is currently a professor of astronomy. Heiles is pivotal in understanding the diffuse gas in the interstellar medium, primarily through observation of the hydrogen line. His role in this field is such important that a conference at Arecibo Observatory in Puerto Rico on diffuse matter was held in honor of Heiles’s 65th birthday. Heiles got Heineman Prize in 1989 for outstanding work in astrophysics. He is also a member of the National Academy of Sciences.
