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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-2035
DTSTART:20101209T213000Z
DURATION:PT1H0M0S
DTSTAMP:20260429T233522Z
LAST-MODIFIED:20101207T150436Z
LOCATION:4421 Sterling Hall
SUMMARY:Gas Accretion in Galaxies\, Astronomy Colloquium\, Dusan Keres
 \, Harvard Smithsonian Center for Astrophysics
DESCRIPTION:&quot\;Most galaxies are actively star forming at all epoc
 hs. However\, observations of dense\, galactic gas indicate that\, at 
 any epoch\, there is not enough gas in galaxies to support evolution o
 f star formation activity over time. This suggests that galactic gas i
 s being replenished from the intergalactic medium.<br><br>
\n<br><br>

 \nI use fully cosmological simulations of galaxy formation to study th
 e gas supply into galactic component from high redshift to present. At
  high redshift &quot\;smooth&quot\; infall of cold filamentary gas dom
 inates the gas supply of all galaxies. This &quot\;cold mode accretion
 &quot\; is unlike the accretion in the standard model of galaxy format
 ion in which cooling of the hot halo atmospheres is a source of gas su
 pply to galaxies. Cold mode accretion is a major driver of very active
  star formation of high-z galaxies enabling such activity to proceed f
 or a significant fraction of the Hubble time. Gas accretion rates at a
  given halo and galaxy mass decrease with time\, causing the drop in s
 tar formation rates. At low redshift hot virialized gas can cool in so
 me of the halos\, but cold gaseous clouds that form from infalling fil
 aments can dominate gas supply in galaxies such as Milky Way.<br><br>

 \n<br><br>
\nIn this talk I will describe properties\, physics and con
 sequences of cold gas accretion from the intergalactic medium as well 
 as predictions for the observational probes of cold halo gas that can 
 provide strong constraints on the models. I will also discuss remainin
 g open questions and future directions in the studies of galactic gas 
 accretion\, including new computational methods and observations with 
 upcoming facilities.&quot\;<br><br>
\n
URL:https://www.physics.wisc.edu/events/?id=2035
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