Year: 2012
Type: article
Abstract: Making use of H i 21 cm line measurements from the ALFALFA survey (α.40) and photometry from the Sloan Digital Sky Survey (SDSS) and Galaxy Evolution Explorer ( GALEX ), we investigate the global scaling relations and fundamental planes linking stars and gas for a sample of 9417 common galaxies: the α.40–SDSS– GALEX sample. In addition to their H i properties derived from the ALFALFA data set, stellar masses ( M * ) and star formation rates (SFRs) are derived from fitting the UV–optical spectral energy distributions. 96% of the α.40–SDSS– GALEX galaxies belong to the blue cloud, with the average gas fraction f H i ≡ M H i / M * ∼ 1.5. A transition in star formation (SF) properties is found whereby below M * ∼ 10 9.5 M ☉ , the slope of the star-forming sequence changes, the dispersion in the specific star formation rate (SSFR) distribution increases, and the star formation efficiency (SFE) mildly increases with M * . The evolutionary track in the SSFR– M * diagram, as well as that in the color–magnitude diagram, is linked to the H i content; below this transition mass, the SF is regulated strongly by the H i . Comparison of H i and optically selected samples over the same restricted volume shows that the H i -selected population is less evolved and has overall higher SFR and SSFR at a given stellar mass, but lower SFE and extinction, suggesting either that a bottleneck exists in the H i -to-H 2 conversion or that the process of SF in the very H i -dominated galaxies obeys an unusual, low-efficiency SF law. A trend is found that, for a given stellar mass, high gas fraction galaxies reside preferentially in dark matter halos with high spin parameters. Because it represents a full census of H i -bearing galaxies at z ∼ 0, the scaling relations and fundamental planes derived for the ALFALFA population can be used to assess the H i detection rate by future blind H i surveys and intensity mapping experiments at higher redshift.
Source: The Astrophysical Journal
Institutions: Cornell University, Leiden University, Leiden Observatory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Princeton University, Ohio State University, University of Washington, Johns Hopkins University, University of Pittsburgh, Case Western Reserve University, Drexel University, Universität Basel, University of Portsmouth, New Mexico State University, Universities Space Research Association, Chinese Academy of Sciences, Max-Planck-Gesellschaft, Max-Planck-Institut für Astronomie, U.S. Naval Observatory, Fermilab, Los Alamos National Laboratory
Awards: ALFALFA: The Arecibo Extragalactic HI Legacy Survey, Harvesting ALFALFA: Tracking the Gas-Rich Halos at z=0, THE ROLE OF ENVIRONMENT IN THE EVOLUTION OF LOW MASS ALFALFA GALAXIES: SUMMARY: WE PROPOSE TO OBTAIN 1.5 KSEC GALEX OBSERVATIONS OF A SET OF NEARBY,, Management and Operations of the Arecibo Observatory (AO), WE PROPOSE TO OBTAIN MODERATE INTEGRATION TARGETED GALEX OBSERVATIONS OF A SAMPLE OF NEARBY LOW MAS, WE PROPOSE TO CONDUCT A CORRELATIVE STUDY OF THE UV FLUX EXTRACTED FROM ARCHIVED GALEX IMAGING DATA, MARTHA P HAYNES/CORNELL UNIVERSITY"STAR FORMATION IN LOW MASS ALFALFA GALAXIES"WE PROPOSE TO COMPLETE A PROGRAM OF TARGETED 1.5 KSEC GALEX OBSERVAT, WE PROPOSE TO OBTAIN 1.5 KSEC GALEX OBSERVATIONS OF A SAMPLE OF MASSIVE GAS-RICH BUT UNDERLUMINOUS GALAXIES DETECTED IN THE HI LINE BY THE CURRENTLY
OpenAlex ID: W1991471447