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Ryan Leaman (MPIA)

Cooling and heating in the Milky Way's Goldilocks disk
When Nov 27, 2015 from 11:00 AM to 12:00 PM
What
  • Special Seminar
  • Colloquium
Where SH, Seminar Room
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I will discuss an effort to constrain the accretion history of the Milky Way (MW), by jointly examining the amount of disk heating (as traced by an increase in stellar velocity dispersion of the disk stars of different ages) experienced by the MW from infalling satellite galaxies, and by considering the populations of Globular Clusters that the accreted satellite galaxies might bring with them to the MW's stellar halo.  Key to this exercise are new semi-analytic estimates for the energy injection of satellites an orbits of arbitrary circularity, and an empirical estimate for the velocity dispersion of the dynamically hot gas that stars in the MW disk might be born out of at high redshift.  I will show that the observed Globular Cluster populations and MW disk structure, are consistent with the MW experiencing a merger history similar to those in cosmological simulations, including one or two 1:10 mass ratio accretion events - provided that the MW's gas disk was already dynamically hot at early times from internal processes (e.g., supernovae feedback and gravitational instabilities).