THE STAR FORMATION LAW AT LOW SURFACE DENSITY

被引：126

作者：

Wyder, Ted K. ^{[1
]}

Martin, D. Christopher ^{[1
]}

Barlow, Tom A. ^{[1
]}

Foster, Karl ^{[1
]}

Friedman, Peter G. ^{[1
]}

Morrissey, Patrick ^{[1
]}

Neff, Susan G. ^{[2
]}

Neill, James D. ^{[1
]}

Schiminovich, David ^{[3
]}

Seibert, Mark ^{[4
]}

Bianchi, Luciana ^{[5
]}

Donas, Jose ^{[6
]}

Heckman, Timothy M. ^{[7
]}

Lee, Young-Wook ^{[8
]}

Madore, Barry F. ^{[4
]}

Milliard, Bruno ^{[6
]}

Rich, R. Michael ^{[9
]}

Szalay, Alex S. ^{[7
]}

Yi, Sukyoung K. ^{[8
]}

机构：

[1] CALTECH, Pasadena, CA 91125 USA

[2] NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA

[3] Columbia Univ, Dept Astron, New York, NY 10027 USA

[4] Observ Carnegie Inst Washington, Pasadena, CA 91101 USA

[5] Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA

[6] Astrophys Lab, F-13376 Marseille 12, France

[7] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA

[8] Yonsei Univ, Ctr Space Astrophys, Seoul 120749, South Korea

[9] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

来源：

ASTROPHYSICAL JOURNAL | 2009年 / 696卷 / 02期

关键词：

galaxies: evolution; galaxies: irregular; galaxies: ISM; galaxies: spiral; ultraviolet: galaxies; BRIGHTNESS DISK GALAXIES; EXTREME OUTER DISK; INTERSTELLAR-MEDIUM; MOLECULAR GAS; FORMATION THRESHOLDS; FORMING GALAXIES; NEARBY GALAXIES; LUMINOSITY FUNCTION; INFRARED PROPERTIES; STARBURST GALAXIES;

D O I：

10.1088/0004-637X/696/2/1834

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We investigate the nature of the star formation law at low gas surface densities using a sample of 19 low surface brightness (LSB) galaxies with existing H I maps in the literature, UV imaging from the Galaxy Evolution Explorer satellite, and optical images from the Sloan Digital Sky Survey. All of the LSB galaxies have (NUV - r) colors similar to those for higher surface brightness star-forming galaxies of similar luminosity indicating that their average star formation histories are not very different. Based upon four LSB galaxies with both UV and far-infrared (FIR) data, we find FIR/UV ratios significantly less than 1, implying low amounts of internal UV extinction in LSB galaxies. We use the UV images and H I maps to measure the star formation rate (SFR) and hydrogen gas surface density within the same region for all the galaxies. The LSB galaxy star formation rate surface densities lie below the extrapolation of the power law fit to the SFR surface density as a function of the total gas density for higher surface brightness galaxies. Although there is more scatter, the LSB galaxies also lie below a second version of the star formation law in which the SFR surface density is correlated with the gas density divided by the orbital time in the disk. The downturn seen in both star formation laws is consistent with theoretical models that predict lower star formation efficiencies in LSB galaxies due to the declining molecular fraction with decreasing density.

引用

页码：1834 / 1853

页数：20

共 76 条

[1] The optical and near-infrared properties of galaxies. I. Luminosity and stellar mass functions [J].