Events at Physics
Events on Friday, November 15th, 2019
- Astronomy Special Talk
- "The SPLASH Survey of the Andromeda Galaxy"
- Time: 11:00 am - 12:00 pm
- Place: 4421 Sterling Hall
- Speaker: Raja GuhaThakurta, UCO/Lick Observatory, University of California Santa Cruz
- Abstract: Our nearest large spiral galaxy neighbor, the Andromeda galaxy (M31), and its dwarf satellites, offer a panoramic yet detailed view of galaxy formation and evolution in our astronomical backyard. This system also serves as an excellent laboratory for the study of stellar populations because the stars are all practically at the same distance from us. I will present results from the SPLASH (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo) survey, the backbone of which was a large Keck DEIMOS spectroscopic survey of evolved stars in M31. Most of the SPLASH spectroscopic targets in M31's disk were selected from the PHAT (Panchromatic Hubble Andromeda Treasury) survey, a wide-field 6-filter Hubble Space Telescope mosaic image of a portion of the disk of M31. The talk will cover a range of science topics including: Local Group dynamics, structure/substructure and metallicity of M31's stellar halo, satellite tidal interactions, disk/halo interface, dynamical heating of the disk, and rare stellar populations.
- Host: Professor Tremonti and Professor Bershady
- Physics Department Colloquium
- Black Hole Ergomagnetospheres, Electromagnetic Jets and Ejection Disks
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Roger Blandford, KIPAC, Stanford
- Abstract: Recent, remarkable images made by the EHT collaboration exhibit a ring of emission, presumably orbiting a six billion solar mass black hole. It is proposed that what is observed is not a gas torus but an extensive “ ergomagnetosphere" that connects mechanically to a much larger ``ejection disk’’ and that, in sources like M87, the electromagnetic jets and the disk are mostly powered by black hole spin, not accretion. Implications for general active galactic nuclei and other sources of relativistic jets will be briefly discussed.
- Host: Cary Forest