%0 Generic %1 Rubin2011 %A Rubin, Kate H. R. %A Prochaska, J. Xavier %A Koo, David C. %A Phillips, Andrew C. %D 2011 %K accretion cold inflow %T The Direct Detection of Cool, Metal-Enriched Gas Accretion onto Galaxies at z ~ 0.5 %U http://arxiv.org/abs/1110.0837 %X We report on the discovery of cool gas inflow toward six star-forming galaxies with redshifts z ~ 0.35 - 1. Analysis of MgII and FeII resonance-line absorption in Keck/LRIS spectroscopy of this sample reveals velocity shifts of 80 - 200 km/s and equivalent widths for inflowing gas of >~ 0.6 Ang in five of the six objects. The host galaxies exhibit a wide range in star formation rates (SFR ~ 1 - 40 M_sun/yr) and have stellar masses similar to that of the Milky Way (log M_*/M_sun ~ 9.6 - 10.5). Imaging from the Hubble Space Telescope Advanced Camera for Surveys indicates that five of the six galaxies have highly inclined (i > 55 deg), disk-like morphologies. These data represent the first unambiguous detection of inflow into isolated, star-forming galaxies in the distant universe. We suggest that the inflow is due to the infall of enriched material from dwarf satellites and/or a galactic fountain within the galaxies. Assuming that the material has been enriched to 0.1Z_sun and has a physical extent approximately equal to that of the galaxies, we infer mass inflow rates of dM_in/dt >~ 0.2 - 3 M_sun/yr for four of these systems. Finally, from comparison of these absorption lines to the profiles of MgII and FeII absorption in a larger spectroscopic sample of ~100 objects, we measure a covering fraction of cool inflow of at least 6%, but cannot rule out the presence of enriched infall onto as many as ~40 of these galaxies.

@misc{Rubin2011, abstract = { We report on the discovery of cool gas inflow toward six star-forming galaxies with redshifts z ~ 0.35 - 1. Analysis of MgII and FeII resonance-line absorption in Keck/LRIS spectroscopy of this sample reveals velocity shifts of 80 - 200 km/s and equivalent widths for inflowing gas of >~ 0.6 Ang in five of the six objects. The host galaxies exhibit a wide range in star formation rates (SFR ~ 1 - 40 M_sun/yr) and have stellar masses similar to that of the Milky Way (log M_*/M_sun ~ 9.6 - 10.5). Imaging from the Hubble Space Telescope Advanced Camera for Surveys indicates that five of the six galaxies have highly inclined (i > 55 deg), disk-like morphologies. These data represent the first unambiguous detection of inflow into isolated, star-forming galaxies in the distant universe. We suggest that the inflow is due to the infall of enriched material from dwarf satellites and/or a galactic fountain within the galaxies. Assuming that the material has been enriched to 0.1Z_sun and has a physical extent approximately equal to that of the galaxies, we infer mass inflow rates of dM_in/dt >~ 0.2 - 3 M_sun/yr for four of these systems. Finally, from comparison of these absorption lines to the profiles of MgII and FeII absorption in a larger spectroscopic sample of ~100 objects, we measure a covering fraction of cool inflow of at least 6%, but cannot rule out the presence of enriched infall onto as many as ~40 of these galaxies. }, added-at = {2011-10-06T20:45:50.000+0200}, author = {Rubin, Kate H. R. and Prochaska, J. Xavier and Koo, David C. and Phillips, Andrew C.}, biburl = {https://www.bibsonomy.org/bibtex/24d2e1ce3585970de665d8df2f85eacfb/miki}, description = {[1110.0837] The Direct Detection of Cool, Metal-Enriched Gas Accretion onto Galaxies at z ~ 0.5}, interhash = {5bab1f2e334c65080fc3422b16567536}, intrahash = {4d2e1ce3585970de665d8df2f85eacfb}, keywords = {accretion cold inflow}, note = {cite arxiv:1110.0837Comment: Submitted to ApJL. 6 pages, 4 figures. Uses emulateapj format}, timestamp = {2011-10-06T20:45:50.000+0200}, title = {The Direct Detection of Cool, Metal-Enriched Gas Accretion onto Galaxies at z ~ 0.5}, url = {http://arxiv.org/abs/1110.0837}, year = 2011 }