Seminar Title:	Extended Schmidt Law: Existing Stars Control How Efficient New Stars Form
Speaker:	Dr. Yong Shi
Affiliation:	(IPAC/Caltech, USA)
When:	Thursday Morning, Dec. 23th, 10:30 a.m
Where:	Room 327, Office Block, 2 West Beijing Road (PMO, CAS)
	Welcome to Attend
	( PMO Academic Committee & Academic Circulating committee)

　Abstract　 

　

  Star forms from interstellar medium. The resulting stellar mass growth, chemical enrichment and energy feedback are key processes of galaxy formation and evolution. While star forms through a series of complicated processes from initial gas collapse to final star formation, an empirical law between star formation rate (SFR) and gas offers critical tests of understandings of star formation processes and have crucial applications to studies of galaxy formation and evolution.

  I will present our recent proposed scaling law -- the extended Schmidt law, a relationship between star formation efficiency (SFR/gas-mass) and stellar mass surface density. Compared to the classical Kennicutt-Schmidt law, this new relation does not break at the low density regime where the KS law does. Comparison with physical models of star formation shows that this relation can be reproduced by models of gas free-fall in a stellar-gravitational potential and pressure-supported star formation.

  By applying it to studies of galaxy formation and evolution, it can re-produce the observed main sequence of star-forming galaxies from z=0 up z=2 without invoking ad hoc mechanisms to delay star formation in low mass galaxies.