Matt Hayes (Stockholm University)

Detecting and characterizing gas accretion and feedback in galaxies
When Jan 21, 2016 from 02:30 PM to 03:30 PM
What
  • Colloquium
Where SH Lecture Hall
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Star formation in galaxies is driven and regulated by the competing forces of gas infall and outflow. On the one hand star-formation must be related by the rate at which gas can be acquired by dark matter halos, cooled, and then compressed into stars. On the other hand, feedback from the star formation process itself heats and accelerates gas in the ISM, which regulates subsequent star formation and shapes the observed relations between the properties of galaxies.  I will present and discuss two new observations that concern gas moving in both directions.

* On the inflow side I will present recent observations obtained with VLT/MUSE, the remarkable sensitivity of which enables us to detect a  large (~200 kpc) filament of diffuse Ly-alpha emitting gas at redshift 3.  I will argue that this gas may fuel the rapid assembly of galaxies inside a high-z protocluster.

* On the outflow side I will present HST observations of warm (log T/K~5.5) gas, as it flows out from a galaxy.  Here we map the emission in the OVI phase for the first time.  The the unique combination of emission and absorption allows us to measure the physical sizes and cooling rate of the coronal gas phase, and place new constraints on the future (position and state) of gas entrained in galaxy outflows.