Speaker：Prof. Douglas Lin (USCS/Tsinghua Univ.)

Time: 3: 00pm, June 28th (Friday)

Tencent Meeting：891-722-604 password: 6360

Location: Big conference room, 3rd floor

Abstract：

he inner parsec of the supermassive black hole (SMBH) in the center of the Milky Way, Sgr A*, contains a cluster of several hundred young, massive stars. Their complex, highly structured kinematics poses an intriguing conundrum on their origin within the strong tidal field close to the SMBH. It has been suggested that the encounter of a gas cloud with the SMBH could produce a fast rotating disk of coeval, massive stars. This result however differs strongly from the observed multi-component orbital distribution. We demonstrate that star-star scattering within the disk can only weakly change their orbits and cannot explain the observations, even if one includes the dispersal of an additional gaseous disk component. Including however the gravitational interaction with a putative intermediate-mass companion (IMC) of Sgr A*, possibly an intermediate mass black hole, naturally scatters the stars into their current kinematic configuration on timescales consistent with their stellar ages.

CV：

Prof. Doug Lin’s wide range of research interests include the formation and dynamics of planetary systems, star formation and interstellar medium, theory of accretion disks, formation and dynamics of star clusters, interacting galaxies, active galactic nuclei and black holes, and gravitational waves. Prof. Doug Lin received his BSc from McGill University and his PhD from the University of Cambridge. He joined the University of California at Santa Cruz in 1979, where he is now Emerita Professor. He was also the Founding Director of the Kavli Institute for Astronomy & Astrophysics at Peking University. He has been awarded the Brouwer Award of the Division on Dynamical Astronomy of the American Astronomical Society and the Bruce Medal of the Astronomical Society of the Pacific. He is a member of the American Academy of Arts and Science, an Honorary Fellow of the Royal Astronomical Society, and a Legacy Fellow of the American Astronomical Society.