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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-3690
DTSTART:20150326T204500Z
DTEND:20150326T220000Z
DTSTAMP:20260419T153834Z
LAST-MODIFIED:20150320T160201Z
LOCATION:4421 Sterling Hall (Coffee and Cookies at 3:30 PM)
SUMMARY:Self-regulated star formation and the diffuse ISM\, Astronomy 
 Colloquium\, Professor Eve Ostriker \, Princeton University
DESCRIPTION:Recent years have seen significant progress in quantifying
  the physics of star formation feedback and its effects on the ISM wit
 hin galactic disks.  In this talk\, I will discuss theory and numerica
 l hydrodynamic simulations that explain and demonstrate how self-regul
 ation is achieved through a set of balances: heating and cooling\, tur
 bulent driving and dissipation\, and gravitational compaction and pres
 sure support.  Because the sources of momentum and energy are directly
  associated with massive star formation\, the requirement of equilibri
 um leads to a prediction for the star formation rate.  The thermal/dyn
 amical equilibrium theory also yields predictions for the ratio of the
 rmal to turbulent pressure\, and for the proportion of warm to cold ga
 s in the diffuse atomic ISM.  Although we find that radiation feedback
  can be important within individual star-forming clouds\, supernovae p
 lay the dominant role in the ISM overall\, because the momentum inject
 ed by Sedov-Taylor blast waves is an order of magnitude greater than o
 ther source terms.  Resolved simulations show that radiative supernova
  remnants inject a momentum ~ 1-4 e5 Msun km/s to the ISM\, insensitiv
 e to the local gas properties.  This momentum yield\, combined with th
 e heating rate from FUV\, is just what is required to explain observed
  large-scale ISM properties and star formation rates.
URL:https://www.physics.wisc.edu/events/?id=3690
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