Star Formation Thresholds in Galactic Disks

Crystal L. Martin, Robert C. Kennicutt, Jr.
2001 Astrophysical Journal  
We report the first results of a detailed study of the star formation law in a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI and H_2 (as traced by CO) surface density profiles, and new CCD photometry. Our results strongly support the view that the formation of gravitationally bound interstellar clouds regulates the onset of widespread star formation -- at least in the outer regions of galactic disks.
doi:10.1086/321452 fatcat:yqx55yypv5gqfk67h2mpjldpay