A TEST OF STAR FORMATION LAWS IN DISK GALAXIES
- Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States), E-mail: jt@astro.ufl.edu
We use observations of the radial profiles of the mass surface density of total, {sigma} {sub g}, and molecular, {sigma}{sub H2}, gas rotation velocity and star formation rate surface density, {sigma}{sub sfr}, of the molecular dominated regions of 12 disk galaxies from Leroy et al. to test several star formation laws: a 'Kennicutt-Schmidt power law', {sigma}{sub sfr} = A{sub g} {sigma}{sup 1.5} {sub g,2}; a 'constant molecular law', {sigma}{sub sfr} = A {sub H2}{sigma}{sub H2,2}; the 'turbulence-regulated laws' of Krumholz and McKee (KM) and Krumholz, McKee, and Tumlinson (KMT), a 'gas-{omega} law', {sigma}{sub sfr} = B {sub {omega}}{sigma} {sub g}{omega}; and a shear-driven 'giant molecular cloud (GMC) collisions law', {sigma}{sub sfr} = B {sub CC}{sigma} {sub g}{omega}(1 - 0.7{beta}), where {beta} {identical_to} d ln v {sub circ}/d ln r. We find the constant molecular law, KMT turbulence law, and GMC collision law are the most accurate, with an rms error of a factor of 1.5 if the normalization constants are allowed to vary between galaxies. Of these three laws, the GMC collision law does not require a change in physics to account for the full range of star formation activity seen from normal galaxies to circumnuclear starbursts. A single global GMC collision law with B {sub CC} = 8.0 x 10{sup -3}, i.e., a gas consumption time of 20 orbital times for {beta} = 0, yields an rms error of a factor of 1.8.
- OSTI ID:
- 21301294
- Journal Information:
- Astrophysical Journal Letters, Vol. 710, Issue 1; Other Information: DOI: 10.1088/2041-8205/710/1/L88; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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