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Polluting the Circumgalactic and Intergalactic Mediums with Metals: Large Scale Outflows of the Large Magellanic Cloud

Event Details

Event Dates: 

Friday, June 6, 2014 - 12:00pm

Seminar Location: 

  • CASA Conference Room C324

Speaker Name(s): 

Kat Barger

Speaker Affiliation(s): 

Notre Dame
Seminar Type/Subject

Scientific Seminar Type: 

  • Astrophysics Lunch Seminar

Event Details & Abstract: 

The weaker gravitational hold of small galaxies means that ejected gas and metals can more readily escape from them. In the Large Magellanic Cloud, galaxy interactions have triggered intense star formation throughout its disk. Evidence for a widespread gaseous outflows driven by this star formation has been seen in previous absorption-line studies toward stars in its disk, with only a small fraction of the sight lines showing gas at velocities consistent with inflows. Using UV Hubble Space Telescope (HST) absorption-line observations towards an AGN and a LMC disk star projected only 100 pc away, we compare and separate the gas flows on both the near- and far-side of the galaxy’s disk. We find that even in this relatively quiescent region of this galaxy, highly ionized (H+/H ≥ 60%) and collisionally dominated gas is funneled away from the disk at outward speeds of ~100 km/s along the line of sight. The relatively symmetric kinematics and properties of these outflows, combined with results of previous studies, provide compelling evidence that this drives a global, large-scale wind that permeates from its entire disk. Similar winds emanating from other small galaxies over comic time could explain how the circumgalactic and intergalactic mediums has been polluted with metals.

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