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CATEGORIES:Institute of Astronomy Colloquia
SUMMARY:How galaxies form stars - Andrey Kravtsov (U Chica
 go)
DTSTART;TZID=Europe/London:20181004T160000
DTEND;TZID=Europe/London:20181004T170000
UID:TALK111697AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/111697
DESCRIPTION:Formation of stars in galaxies is a complex multi-
 scale process. One of the big puzzles about star f
 ormation was that observations show that galaxies 
 convert their gas (molecular and atomic) into star
 s on a time scale of ~5-10 Gyrs\, which is much lo
 nger than time scales of any relevant processes in
  the ISM and is also considerably longer than the 
 corresponding conversion time scale in star-formin
 g molecular clouds.\n\nIn addition\, observations 
 over the past decade showed that star formation ra
 te in observed regular (non-star burst) galaxies s
 cales almost linearly with *molecular* gas mass\, 
 with the coefficient of proportionality\, the depl
 etion time = M_H2/SFR of about 2 Gyrs with a relat
 ively small scatter\, even though scatter is large
  on the scale of star forming clouds.\n\nMany gala
 xy formation simulations could reproduce the obser
 ved value of depletion time\, but the physics cont
 rolling it\, its dependence on assumptions made ab
 out star formation\, and the slope of the relation
  was not understood. I will present results of a s
 uite of simulations that we used to explore this b
 ehavior systematically and a simple physical model
  that explains the physics behind both the observe
 d long gas depletion times in galaxies and the lin
 ear relation between molecular gas mass and star f
 ormation rate.\n
LOCATION:Sackler Lecture Theatre\, IoA (tea at 3:30 pm)
CONTACT:
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