Astrophysics Lectures - The Gas Around Galaxies - Yuguang Chen - 04/10/2020

Astronomers still don't fully understand why galaxies behave as they do, but the key to understanding them lies in the recently discovered large gas clouds surrounding them known as the circumgalactic medium. Timestamps below: 00:00 Announcements 02:16 What does the sky look like tonight? 05:25 Intro to Galaxies Presentation 06:18 Galaxies Presentation 40:20 Q&A Panel Introductions 41:54 Q&A Panel 2:02:59 Concluding Remarks Speaker: Yuguang Chen Title: The Circumgalactic Medium: The Gas Around Galaxies Abstract: The galaxies that we are familiar with are only a tiny tip of a giant iceberg. In 1969, astronomers John Bahcall and Lyman Spitzer proposed that all galaxies are embedded in massive, enormous gas clouds. It is only in the last decade that we have developed efficient tools to detect and probe the details of these clouds, which are now known as the “circumgalactic medium”. But what is the nature of this gas? How do we study it? And how does it affect how galaxies like our Milky Way form and evolve over cosmic time? I will address these questions and introduce you to this exciting frontier in astronomy. Panelists: --Yuguang Chen is a PhD candidate. His specialty is on the circumgalactic medium and the evolution of galaxies. To study these, he uses the largest telescopes in optical and infrared. --Dr. Cameron Hummels is a postdoctoral researcher in the department who studies how galaxies form and evolve using detailed supercomputer simulations. --Nicole Wallack is a PhD candidate in planetary science who uses space and ground based telescopes to study the atmospheres of planets around other stars to try to understand how planets form and evolve. -- Kishalay De is a PhD candidate in the department who uses optical and infrared telescopes to find and study cosmic explosions to understand the formation and fates of dead stellar remnants in distant galaxies. --Anna Ho is a graduate student who investigates the violent deaths, death omens, and afterlives of stars. --Michael Zhang is a graduate student in Caltech Astronomy who studies the atmospheres of planets around other stars, particularly small rocky planets. The Stellarium software package for visualizing the night sky is available free on Windows, Mac, and Linux at https://stellarium.org/ .