MN Institute for Astrophysics Colloquium

semester, 2019


Friday, January 25th 2019
There will be no colloquium this week. (Faculty candidate presentation on Thursday).

Friday, February 1st 2019
There will be no colloquium this week

Wednesday, February 6th 2019
1:25 pm:
Speaker: Richard Anthony D'Souza, University of Michigan
Subject: Unravelling the Andromeda Galaxy's most important merger

The Andromeda Galaxy (M31), our nearest large galactic neighbour, offers a unique opportunity to test how mergers affect galaxy properties. M31's stellar halo caused by the tidal disruption of satellite galaxies is the best tracer of the galaxy's accretion history. Despite a decade of effort in mapping out M31's large stellar halo, we are unable to convert M31's stellar halo into a merger history. Here we use cosmological models of galaxy formation to show that M31's massive and metal-rich stellar halo containing intermediate age stars implies that it merged with a large (M* ~ 2.5 x 10^10 M_sun) galaxy ~2 Gyr ago. The simulated properties of the merger debris help to interpret a broader set of observations of M31's stellar halo and satellites than previously considered: its compact and metal-rich satellite M32 is the tidally-stripped core of the disrupted galaxy, M31's rotating and flattened inner stellar halo contains most of the merger debris, and the giant stellar stream is likely to have been thrown out during the merger. This accreted galaxy was the third largest member of the Local Group. This merger may explain the global burst of star formation ~2 Gyr ago in the disk of M31 in which ~1/5 of its stars were formed. Moreover, M31's disk and bulge were already in place before its most important merger, suggesting that mergers of this magnitude do not dramatically affect galaxy structure.

Faculty Host: Evan Skillman

Friday, February 8th 2019
There will be no colloquium this week. (Faculty candidate presentation on Thursday).

Friday, February 15th 2019
There will be no colloquium this week. (Faculty candidate presentation on Thursday).

Friday, February 22nd 2019
2:30 pm:
Speaker: Anna Williams, Macalester University

Friday, March 1st 2019
2:30 pm:
Speaker:  Dale Gary, New Jersey Institute of Technology
Subject: TBD
Faculty Host: John Wygant

Friday, March 8th 2019
2:30 pm:
Speaker: Marc Pinsonneault, The Ohio State University

Friday, March 15th 2019
2:30 pm:
Speaker: TBD

Friday, March 22nd 2019
2:30 pm:
There will be be no colloquium this week due to spring break

Friday, March 29th 2019
2:30 pm:
Speaker: Vuk Mandic
Subject: TBD
Faculty Host: Evan Skillman

Friday, April 5th 2019
2:00 pm:
Speaker: Rob Kennicutt, Texas A&M University
Subject: 2020 Decadal Survey

Friday, April 12th 2019
2:30 pm:
Speaker: Eliot Quataert, UC Berkeley

Friday, April 19th 2019
2:30 pm:
Speaker: Peter Garnovich, University of Notre Dame
Subject: TBD
Faculty Host: Patrick Kelly

Friday, April 26th 2019
2:30 pm:
Speaker: TBD
Faculty Host: Charles E. Woodward

Friday, May 3rd 2019
2:30 pm:
There will be no colloquium this week

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