<< May 2015 >>
Sun Mon Tue Wed Thu Fri Sat
   1   2 
 3   4   5   6   7   8   9 
 10   11   12   13   14   15   16 
 17   18   19   20   21   22   23 
 24   25   26   27   28   29   30 
Add an Event Edit This Event

Events at Physics

<< Spring 2015 Summer 2015 Fall 2015 >>
Subscribe to receive email announcements of events
Astronomy Colloquium
A "New" Galaxy Formation Mechanism from Joint Galactic and High Redshift Constraints
Date: Thursday, May 14th
Time: 3:45 pm
Place: 4421 Sterling Hall
Speaker: Jonathan Bird, Vanderbilt University

Very different data sets guide galaxy formation theory across cosmic history: from the global properties of >10^7 galaxies at high redshift (z>0.5) to the kinematics and chemistry of >10^6 stars here in the Milky Way. Traditional observational and computational limitations have dictated independent study of these two regimes. I will discuss how this picture is changing rapidly and how viewing the MW as important boundary condition on galaxy evolution puts unprecedented demands on galaxy formation theory. In particular, I will discuss a novel disk formation mechanism and its signature in current observations of the Milky Way and the resolved kinematics of high redshift galaxies.

Modern, high-resolution, cosmological galaxy formation simulations reveal that disks can grow ‘upside-down’ in the sense that progressively younger stellar populations are born with increasingly smaller vertical velocity dispersion, tracing the kinematics of the collapsing gas disk from which they form. We find that the upside-down model matches the most stringent observational constraints here in the MW, including the steep stellar age-velocity relationship measured in the solar neighborhood. I will argue that traditional interpretations of disk evolution from MW data contradict evidence from Integral Field Unit observations of high-redshift disk galaxies and must be revised. Our findings suggest that the ‘upside-down’ model is currently the only self-consistent formation mechanism able to match kinematic constraints from z~2 to z~0. I will conclude with preliminary, yet tantalizing, evidence connecting the star formation history of simulated galaxies with their detailed morphology.

Host: Professor Matt Bershady
Add this event to your calendar

©2013 Board of Regents of the University of Wisconsin System