%0 Generic %1 Geach2011 %A Geach, James E. %A Smail, Ian %A Moran, Sean M. %A MacArthur, Lauren A. %A del P. Lagos, Claudia %A Edge, Alastair C. %D 2011 %K galaxy high-z molecules %T On the evolution of the molecular gas fraction of star forming galaxies %U http://arxiv.org/abs/1102.3694 %X We present IRAM Plateau de Bure interferometric detections of CO(1-0) emission from a 24um-selected sample of star-forming galaxies at z=0.4. The galaxies have PAH 7.7um-derived star formation rates of SFR~30-60 M_Sun/yr and stellar masses M*~10^11 M_Sun. The CO(1-0) luminosities of the galaxies imply that the disks still contain a large reservoir of molecular gas, contributing ~20% of the baryonic mass, but have star-formation 'efficiencies' similar to local quiescent disks and gas-dominated disks at z~1.5-2. We reveal evidence that the average molecular gas fraction has undergone strong evolution since z~2, with f_gas ~ (1+z)^2 +/- 0.5. The evolution of f_gas encodes fundamental information about the relative depletion/replenishment of molecular fuel in galaxies, and is expected to be a strong function of halo mass. We show that the latest predictions for the evolution of the molecular gas fraction in semi-analytic models of galaxy formation within a LCDM Universe are supported by these new observations.

@misc{Geach2011, abstract = { We present IRAM Plateau de Bure interferometric detections of CO(1-0) emission from a 24um-selected sample of star-forming galaxies at z=0.4. The galaxies have PAH 7.7um-derived star formation rates of SFR~30-60 M_Sun/yr and stellar masses M*~10^{11} M_Sun. The CO(1-0) luminosities of the galaxies imply that the disks still contain a large reservoir of molecular gas, contributing ~20% of the baryonic mass, but have star-formation 'efficiencies' similar to local quiescent disks and gas-dominated disks at z~1.5-2. We reveal evidence that the average molecular gas fraction has undergone strong evolution since z~2, with f_gas ~ (1+z)^{2 +/- 0.5}. The evolution of f_gas encodes fundamental information about the relative depletion/replenishment of molecular fuel in galaxies, and is expected to be a strong function of halo mass. We show that the latest predictions for the evolution of the molecular gas fraction in semi-analytic models of galaxy formation within a LCDM Universe are supported by these new observations. }, added-at = {2011-02-21T18:20:43.000+0100}, author = {Geach, James E. and Smail, Ian and Moran, Sean M. and MacArthur, Lauren A. and del P. Lagos, Claudia and Edge, Alastair C.}, biburl = {https://www.bibsonomy.org/bibtex/2ac36d6b8b8dd18556ceb22a7ebc572bb/miki}, description = {[1102.3694] On the evolution of the molecular gas fraction of star forming galaxies}, interhash = {3cf903cec54cbd48eb77f94fdd8c992f}, intrahash = {ac36d6b8b8dd18556ceb22a7ebc572bb}, keywords = {galaxy high-z molecules}, note = {cite arxiv:1102.3694 Comment: Accepted for publication in ApJ Letters; 5 pages, 2 figures}, timestamp = {2011-02-21T18:20:43.000+0100}, title = {On the evolution of the molecular gas fraction of star forming galaxies}, url = {http://arxiv.org/abs/1102.3694}, year = 2011 }