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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20160405T123000
DTEND;TZID=Atlantic/Canary:20160405T133000
UID:iactalks-916
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/916
CREATED:2016-04-05T12:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Star formation and molecular hydrogen in dwarf galaxies
DESCRIPTION:Star formation and molecular hydrogen in dwarf galaxies\nDr. Ch
 ia-Yu Hu\n\nWe study the connection of star formation to atomic (HI) and m
 olecular hydrogen (H2) in isolated, low metallicity dwarf galaxies with hi
 gh-resolution SPH simulations. The model includes self-gravity, non-equili
 brium cooling, shielding from an interstellar radiation field, the chemist
 ry of H2 formation, H2-independent star formation, supernova feedback and 
 metal enrichment. We find that the H2 mass fraction is sensitive to the ad
 opted dust-to-gas ratio and the strength of the interstellar radiation fie
 ld, while the star formation rate is not. Star formation is regulated by s
 tellar feedback, keeping the gas out of thermal equilibrium for densities 
 n < 1 cm-3. Because of the long chemical timescales, the H2 mass remain
 s out of chemical equilibrium throughout the simulation. Star formation is
  well-correlated with cold gas, but this dense and cold gas - the reservoi
 r for star formation - is dominated by HI, not H2. In addition, a signific
 ant fraction of H2 resides in a diffuse, warm phase, which is not star-for
 ming. The cold gas fraction is regulated by feedback at small radii and by
  the assumed radiation field at large radii. The decreasing cold gas fract
 ions result in a rapid increase in depletion time (up to 100 Gyr) for tota
 l gas surface densities, in agreement with observations of dwarf galaxies 
 in the Kennicutt-Schmidt plane.
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