CARMA SURVEY TOWARD INFRARED-BRIGHT NEARBY GALAXIES (STING). II. MOLECULAR GAS STAR FORMATION LAW AND DEPLETION TIME ACROSS THE BLUE SEQUENCE

Journal Article · Wed Feb 01 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/745/2/183· OSTI ID:22011702

Rahman, Nurur; Bolatto, Alberto D; Fisher, David B; Vogel, Stuart N ^[1]; Rui, Xue; Wong, Tony ^[2]; Leroy, Adam K ^[3]; Walter, Fabian ^[4]; Bigiel, Frank ^[5]; Rosolowsky, Erik ^[6]; Blitz, Leo ^[7]; West, Andrew A ^[8]; Ott, Juergen ^[9]

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1. Department of Astronomy, University of Maryland, College Park, MD (United States)
2. Department of Astronomy, University of Illinois, Urbana-Champaign, IL (United States)
3. National Radio Astronomy Observatory, Charlottesville, VA (United States)
4. Max-Planck-Institute fur Astronomie, Heidelberg (Germany)
5. Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, D-69120 Heidelberg (Germany)
6. I. K. Barber School of the Arts and Science, University of British-Columbia, Kelowna, BC (Canada)
7. Department of Astronomy, University of California, Berkeley, CA (United States)
8. Department of Astronomy, Boston University, Boston, MA (United States)
9. National Radio Astronomy Observatory, Socorro, NM (United States)

We present an analysis of the relationship between molecular gas and current star formation rate surface density at sub-kiloparsec and kiloparsec scales in a sample of 14 nearby star-forming galaxies. Measuring the relationship in the bright, high molecular gas surface density ({Sigma}{sub H{sub 2}}{approx}>20 M{sub Sun} pc{sup -2}) regions of the disks to minimize the contribution from diffuse extended emission, we find an approximately linear relation between molecular gas and star formation rate surface density, N{sub mol} {approx} 0.96 {+-} 0.16, with a molecular gas depletion time, {tau}{sup mol}{sub dep} {approx} 2.30 {+-} 1.32 Gyr. We show that in the molecular regions of our galaxies there are no clear correlations between {tau}{sup mol}{sub dep} and the free-fall and effective Jeans dynamical times throughout the sample. We do not find strong trends in the power-law index of the spatially resolved molecular gas star formation law or the molecular gas depletion time across the range of galactic stellar masses sampled (M{sub *} {approx} 10{sup 9.7}-10{sup 11.5} M{sub Sun }). There is a trend, however, in global measurements that is particularly marked for low-mass galaxies. We suggest that this trend is probably due to the low surface brightness CO J = 1-0, and it is likely associated with changes in CO-to-H{sub 2} conversion factor.

• OSTI ID: 22011702
• Journal Information: Astrophysical Journal, Vol. 745, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BRIGHTNESS
DENSITY
GALAXIES
HYDROGEN
MASS
STARS