The star formation law at low surface density

Ted K. Wyder; D. Christopher Martin; Tom A. Barlow; Karl Foster; Peter G. Friedman; Patrick Morrissey; Susan G. Neff; James D. Neill; David Schiminovich; Mark Seibert; Luciana Bianchi; José Donas; Timothy M. Heckman; Young Wook Lee; Barry F. Madore; Bruno Milliard; R. Michael Rich; Alex S. Szalay; Sukyoung K. Yi

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

The star formation law at low surface density

Ted K. Wyder, D. Christopher Martin, Tom A. Barlow, Karl Foster, Peter G. Friedman, Patrick Morrissey, Susan G. Neff, James D. Neill, David Schiminovich, Mark Seibert, Luciana Bianchi, José Donas, Timothy M. Heckman, Young Wook Lee, Barry F. Madore, Bruno Milliard, R. Michael Rich, Alex S. Szalay, Sukyoung K. Yi

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105 Citations (Scopus)

Abstract

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 HI 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 HI 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.

Original language	English
Pages (from-to)	1834-1853
Number of pages	20
Journal	Astrophysical Journal
Volume	696
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/696/2/1834
Publication status	Published - 2009 May 10

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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

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Wyder, T. K., Martin, D. C., Barlow, T. A., Foster, K., Friedman, P. G., Morrissey, P., Neff, S. G., Neill, J. D., Schiminovich, D., Seibert, M., Bianchi, L., Donas, J., Heckman, T. M., Lee, Y. W., Madore, B. F., Milliard, B., Rich, R. M., Szalay, A. S., & Yi, S. K. (2009). The star formation law at low surface density. Astrophysical Journal, 696(2), 1834-1853. https://doi.org/10.1088/0004-637X/696/2/1834

@article{9492c9505b604ed6a601c417c0145176,

title = "The star formation law at low surface density",

abstract = "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 HI 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 HI 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.",

author = "Wyder, {Ted K.} and Martin, {D. Christopher} and Barlow, {Tom A.} and Karl Foster and Friedman, {Peter G.} and Patrick Morrissey and Neff, {Susan G.} and Neill, {James D.} and David Schiminovich and Mark Seibert and Luciana Bianchi and Jos{\'e} Donas and Heckman, {Timothy M.} and Lee, {Young Wook} and Madore, {Barry F.} and Bruno Milliard and Rich, {R. Michael} and Szalay, {Alex S.} and Yi, {Sukyoung K.}",

year = "2009",

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doi = "10.1088/0004-637X/696/2/1834",

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Wyder, TK, Martin, DC, Barlow, TA, Foster, K, Friedman, PG, Morrissey, P, Neff, SG, Neill, JD, Schiminovich, D, Seibert, M, Bianchi, L, Donas, J, Heckman, TM, Lee, YW, Madore, BF, Milliard, B, Rich, RM, Szalay, AS & Yi, SK 2009, 'The star formation law at low surface density', Astrophysical Journal, vol. 696, no. 2, pp. 1834-1853. https://doi.org/10.1088/0004-637X/696/2/1834

TY - JOUR

T1 - The star formation law at low surface density

AU - Wyder, Ted K.

AU - Martin, D. Christopher

AU - Barlow, Tom A.

AU - Foster, Karl

AU - Friedman, Peter G.

AU - Morrissey, Patrick

AU - Neff, Susan G.

AU - Neill, James D.

AU - Schiminovich, David

AU - Seibert, Mark

AU - Bianchi, Luciana

AU - Donas, José

AU - Heckman, Timothy M.

AU - Lee, Young Wook

AU - Madore, Barry F.

AU - Milliard, Bruno

AU - Rich, R. Michael

AU - Szalay, Alex S.

AU - Yi, Sukyoung K.

PY - 2009/5/10

Y1 - 2009/5/10

N2 - 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 HI 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 HI 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.

AB - 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 HI 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 HI 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.

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

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VL - 696

SP - 1834

EP - 1853

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -

The star formation law at low surface density

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