%0 Generic %1 moller2017observations %A Møller, P. %A Christensen, L. %A Zwaan, M. A. %A Kanekar, N. %A Prochaska, J. X. %A Rhodin, N. H. P. %A Dessauges-Zavadsky, M. %A Fynbo, J. P. U. %A Neeleman, M. %A Zafar, T. %D 2017 %K CO DLA gas molecular %R 10.1093/mnras/stx2845 %T ALMA + VLT observations of a Damped Lyman-\alpha absorbing galaxy: Massive, wide CO emission, gas-rich but with very low SFR %U http://arxiv.org/abs/1711.00407 %X We are undertaking an ALMA survey of molecular gas in galaxies selected for their strong HI absorption, so-called DLA/sub-DLA galaxies. Here we report CO(2-1) detection from a DLA galaxy at z = 0.716. We also present optical and near-infrared spectra of the galaxy revealing OII, H\alpha and NII emission lines shifted by ~170 km/s relative to the DLA, and providing an oxygen abundance 3.2 times solar, similar to the absorption metallicity. We report low unobscured SFR ~1 Msun/yr given the large reservoir of molecular gas, and also modest obscured SFR=4.5(+4.4,-2.6) Msun/yr based on far-IR and sub-mm data. We determine mass components of the galaxy: logM*/Msun = 10.80(+0.07,-0.14), logM mol-gas/Msun = 10.37 +/-0.04, and logM dust/Msun = 8.45(+0.10,-0.30). Surprisingly, this HI absorption-selected galaxy has no equivalent objects in CO surveys of flux-selected samples. The galaxy falls off current scaling relations for the SFR to molecular gas mass and CO Tully-Fisher relation. Detailed comparison of kinematical components of the absorbing, ionized and molecular gas, combined with their spatial distribution, suggests that part of the CO gas is both kinematically and spatially de-coupled from the main galaxy. It is thus possible that a major star burst in the past could explain the wide CO profile as well as the low SFR. Support for this also comes from the SED favouring an instantaneous burst of age ~0.5 Gyr. Our survey will establish whether flux-selected surveys of molecular gas are missing a key stage in the evolution of galaxies and their conversion of gas to stars.

@misc{moller2017observations, abstract = {We are undertaking an ALMA survey of molecular gas in galaxies selected for their strong HI absorption, so-called DLA/sub-DLA galaxies. Here we report CO(2-1) detection from a DLA galaxy at z = 0.716. We also present optical and near-infrared spectra of the galaxy revealing [OII], H{\alpha} and [NII] emission lines shifted by ~170 km/s relative to the DLA, and providing an oxygen abundance 3.2 times solar, similar to the absorption metallicity. We report low unobscured SFR ~1 Msun/yr given the large reservoir of molecular gas, and also modest obscured SFR=4.5(+4.4,-2.6) Msun/yr based on far-IR and sub-mm data. We determine mass components of the galaxy: log[M*/Msun] = 10.80(+0.07,-0.14), log[M mol-gas/Msun] = 10.37 +/-0.04, and log[M dust/Msun] = 8.45(+0.10,-0.30). Surprisingly, this HI absorption-selected galaxy has no equivalent objects in CO surveys of flux-selected samples. The galaxy falls off current scaling relations for the SFR to molecular gas mass and CO Tully-Fisher relation. Detailed comparison of kinematical components of the absorbing, ionized and molecular gas, combined with their spatial distribution, suggests that part of the CO gas is both kinematically and spatially de-coupled from the main galaxy. It is thus possible that a major star burst in the past could explain the wide CO profile as well as the low SFR. Support for this also comes from the SED favouring an instantaneous burst of age ~0.5 Gyr. Our survey will establish whether flux-selected surveys of molecular gas are missing a key stage in the evolution of galaxies and their conversion of gas to stars.}, added-at = {2017-11-02T10:30:46.000+0100}, author = {Møller, P. and Christensen, L. and Zwaan, M. A. and Kanekar, N. and Prochaska, J. X. and Rhodin, N. H. P. and Dessauges-Zavadsky, M. and Fynbo, J. P. U. and Neeleman, M. and Zafar, T.}, biburl = {https://www.bibsonomy.org/bibtex/2478f38e54c6951b12877b6a35898ae63/miki}, description = {[1711.00407] ALMA + VLT observations of a Damped Lyman-{\alpha} absorbing galaxy: Massive, wide CO emission, gas-rich but with very low SFR}, doi = {10.1093/mnras/stx2845}, interhash = {d39de3bdb3e2438121a8f1798f19bd9f}, intrahash = {478f38e54c6951b12877b6a35898ae63}, keywords = {CO DLA gas molecular}, note = {cite arxiv:1711.00407Comment: Accepted (on All Hallows' Eve 2017) for publication in MNRAS}, timestamp = {2017-11-02T10:30:46.000+0100}, title = {ALMA + VLT observations of a Damped Lyman-{\alpha} absorbing galaxy: Massive, wide CO emission, gas-rich but with very low SFR}, url = {http://arxiv.org/abs/1711.00407}, year = 2017 }