%0 Generic %1 dessaugeszavadsky2014molecular %A Dessauges-Zavadsky, M. %A Zamojski, M. %A Schaerer, D. %A Combes, F. %A Egami, E. %A Swinbank, A. M. %A Richard, J. %A Sklias, P. %A Rawle, T. D. %A Rex, M. %A Kneib, J. P. %A Boone, F. %A Blain, A. %D 2014 %K gas lensed low mass molecular %T Molecular gas content in strongly-lensed z~1.5-3 star-forming galaxies with low IR luminosities %U http://arxiv.org/abs/1408.0816 %X To extend the molecular gas measurements to typical star-forming galaxies (SFGs) with SFR < 40 Msun yr^-1 and M* < 2.5x10^10 Msun at z~1.5-3, we have observed CO emission with the IRAM Plateau de Bure Interferometer and 30m telescope for five strongly-lensed galaxies selected from the Herschel Lensing Survey. These observations are combined with a compilation of CO measurements from the literature. From this, we infer the luminosity correction factors r2,1 = 0.8 and r3,1 = 0.65 of the CO rotational levels J=2 and J=3, respectively, valid for SFGs and sub-mm galaxies at z>1. The combined sample of CO-detected SFGs at z>1 shows a large spread in star formation efficiency (SFE), such that SFE extend beyond the low values of local spirals and overlap the distribution of z>1 sub-mm galaxies. We find that the spread in SFE (or equivalently in molecular gas depletion timescale) is due to primarily the specific star formation rate, but also stellar mass and redshift. Correlations of SFE with the offset from the main-sequence and the compactness of the starburst are less clear. The increase of the molecular gas depletion timescale with M* now revealed by low M* SFGs at z>1 is opposed to the admitted constant molecular gas depletion timescale and the linear Kennicutt-Schmidt relation. We confirm an increase of the molecular gas fraction (fgas) from z~0.2 to z~1.2, followed by a quasi non-evolution toward higher redshifts. At each redshift fgas shows a large dispersion due to the dependence of fgas on M*, producing a gradient of increasing fgas with decreasing M*. We provide the first measure of fgas of z>1 SFGs at the low-M* end (10^9.4 < M*/Msun < 10^9.9), reaching a mean fgas = 0.67+/-0.20 which shows a clear fgas upturn. Finally, we find evidence for a non-universal dust-to-gas ratio among high-redshift SFGs and sub-mm galaxies, local spirals and ULIRGs with near-solar metallicities.

@misc{dessaugeszavadsky2014molecular, abstract = {To extend the molecular gas measurements to typical star-forming galaxies (SFGs) with SFR < 40 Msun yr^{-1} and M* < 2.5x10^{10} Msun at z~1.5-3, we have observed CO emission with the IRAM Plateau de Bure Interferometer and 30m telescope for five strongly-lensed galaxies selected from the Herschel Lensing Survey. These observations are combined with a compilation of CO measurements from the literature. From this, we infer the luminosity correction factors r2,1 = 0.8 and r3,1 = 0.65 of the CO rotational levels J=2 and J=3, respectively, valid for SFGs and sub-mm galaxies at z>1. The combined sample of CO-detected SFGs at z>1 shows a large spread in star formation efficiency (SFE), such that SFE extend beyond the low values of local spirals and overlap the distribution of z>1 sub-mm galaxies. We find that the spread in SFE (or equivalently in molecular gas depletion timescale) is due to primarily the specific star formation rate, but also stellar mass and redshift. Correlations of SFE with the offset from the main-sequence and the compactness of the starburst are less clear. The increase of the molecular gas depletion timescale with M* now revealed by low M* SFGs at z>1 is opposed to the admitted constant molecular gas depletion timescale and the linear Kennicutt-Schmidt relation. We confirm an increase of the molecular gas fraction (fgas) from z~0.2 to z~1.2, followed by a quasi non-evolution toward higher redshifts. At each redshift fgas shows a large dispersion due to the dependence of fgas on M*, producing a gradient of increasing fgas with decreasing M*. We provide the first measure of fgas of z>1 SFGs at the low-M* end (10^{9.4} < M*/Msun < 10^{9.9}), reaching a mean fgas = 0.67+/-0.20 which shows a clear fgas upturn. Finally, we find evidence for a non-universal dust-to-gas ratio among high-redshift SFGs and sub-mm galaxies, local spirals and ULIRGs with near-solar metallicities.}, added-at = {2014-08-06T09:59:05.000+0200}, author = {Dessauges-Zavadsky, M. and Zamojski, M. and Schaerer, D. and Combes, F. and Egami, E. and Swinbank, A. M. and Richard, J. and Sklias, P. and Rawle, T. D. and Rex, M. and Kneib, J. P. and Boone, F. and Blain, A.}, biburl = {https://www.bibsonomy.org/bibtex/24b8c16a3cb78baffc991dca22612e05f/miki}, description = {[1408.0816] Molecular gas content in strongly-lensed z~1.5-3 star-forming galaxies with low IR luminosities}, interhash = {32844e7147971d5ff2db051f3c019988}, intrahash = {4b8c16a3cb78baffc991dca22612e05f}, keywords = {gas lensed low mass molecular}, note = {cite arxiv:1408.0816Comment: 21 pages, 16 figures. Submitted to A&A}, timestamp = {2014-08-06T09:59:05.000+0200}, title = {Molecular gas content in strongly-lensed z~1.5-3 star-forming galaxies with low IR luminosities}, url = {http://arxiv.org/abs/1408.0816}, year = 2014 }