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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 709982.0, MPI für Astronomie / Publikationen_mpia
ALLSMOG: an APEX Low-redshift Legacy Survey for MOlecular Gas - I. Molecular gas scaling relations, and the effect of the CO/H2 conversion factor
Authors:Bothwell, M. S.; Wagg, J.; Cicone, C.; Maiolino, R.; Møller, P.; Aravena, M.; De Breuck, C.; Peng, Y.; Espada, D.; Hodge, J. A.; Impellizzeri, C. M. V.; Martín, S.; Riechers, D.; Walter, F.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:Monthly Notices of the Royal Astronomical Society
Issue / Number:3
Start Page:2599
End Page:2620
Audience:Not Specified
Abstract / Description:We present ALLSMOG, the APEX Low-redshift Legacy Survey for MOlecular Gas. ALLSMOG is a survey designed to observe the CO(2 - 1) emission line with the APEX telescope, in a sample of local galaxies (0.01 < z < 0.03), with stellar masses in the range 8.5 < log(M*/M&sun;) < 10. This paper is a data release and initial analysis of the first two semesters of observations, consisting of 42 galaxies observed in CO(2 - 1). By combining these new CO(2 - 1) emission line data with archival H I data and SDSS optical spectroscopy, we compile a sample of low-mass galaxies with well-defined molecular gas masses, atomic gas masses, and gas-phase metallicities. We explore scaling relations of gas fraction and gas consumption time-scale, and test the extent to which our findings are dependent on a varying CO/H2 conversion factor. We find an increase in the H2/H I mass ratio with stellar mass which closely matches semi-analytic predictions. We find a mean molecular gas fraction for ALLSMOG galaxies of MH2/M* = (0.09-0.13), which decreases with stellar mass. This decrease in total gas fraction with stellar mass is in excess of some model predictions at low stellar masses. We measure a mean molecular gas consumption time-scale for ALLSMOG galaxies of 0.4-0.7 Gyr. We also confirm the non-universality of the molecular gas consumption time-scale, which varies (with stellar mass) from &tilde;100 Myr to &tilde;2 Gyr. Importantly, we find that the trends in the H2/H I mass ratio, gas fraction, and the non-universal molecular gas consumption time-scale are all robust to a range of recent metallicity-dependent CO/H2 conversion factors.
Free Keywords:galaxies: abundances; galaxies: evolution; galaxies: formation; galaxies: statistics
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0035-8711 %R 10.1093/mnras/stu1936
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