Exploring the Supermassive Black Hole at the Galactic Center and the Star Formation History in its Environment

Abstract: As the closest galactic nucleus, the Galactic center provides a unique opportunity to study the supermassive black hole at the center of the Milky Way, Sgr A*, and the formation of the stellar population in this environment. In this talk I will present the long-term accretion properties of Sgr A*, utilizing the longest time baseline considered thus far. I will then introduce a new window on the star formation history at the Galactic center. The limitation in our current understanding of the nuclear star cluster (NSC) star formation history is that previous studies assumed that all stars have solar metallicity. However, age and metallicity are degenerate parameters; by ignoring the effect of metallicities, the age estimates can be biased. Recent spectroscopic surveys showed a significant spread in the metallicity of stars, which motivates us to revisit the star formation. I will present, for the first time, the NSC's star formation history incorporating metallicity constraints derived from a large sample of metallicity measurements obtained from Gemini and the VLT. The analysis shows significantly different star formation history than previously published works. Furthermore, we test different initial mass functions, and present more accurate estimates of the number of compact objects and gravitational-wave merger rates. I will also provide a brief overview of the Panchromatic Hubble Andromeda Southern Treasury (PHAST) survey, a project in which I am actively engaged.

Dr. Zhuo Chen (陈卓, University of Washington)
Hybrid meeting: KIAA first meeting room The zoom link is as follows: Zoom Meeting ID: 878 6573 2980, Passcode: astroPKU, Link: https://us02web.zoom.us/j/87865732980?pwd=VmNqQkxXM21WVzBibnA1TmNxa0Radz09
Wednesday, June 7, 2023 - 1:30PM to Wednesday, June 7, 2023 - 2:30PM