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Title: Resolved H I imaging of a population of massive H I-rich galaxies with suppressed star formation

Despite the existence of well-defined relationships between cold gas and star formation, there is evidence that some galaxies contain large amounts of H I that do not form stars efficiently. By systematically assessing the link between H I and star formation within a sample of galaxies with extremely high H I masses (log M{sub H{sub I}}/M{sub ☉} > 10), we uncover a population of galaxies with an unexpected combination of high H I masses and low specific star formation rates that exists primarily at stellar masses greater than log M{sub *}/M{sub ☉} ∼ 10.5. We obtained H I maps of 20 galaxies in this population to understand the distribution of the H I and the physical conditions in the galaxies that could be suppressing star formation in the presence of large quantities of H I. We find that all of the galaxies we observed have low H I surface densities in the range in which inefficient star formation is common. The low H I surface densities are likely the main cause of the low specific star formation rates, but there is also some evidence that active galactic nuclei or bulges contribute to the suppression of star formation. The sample's agreementmore » with the global star formation law highlights its usefulness as a tool for understanding galaxies that do not always follow expected relationships.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4]
  1. Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)
  2. Swinburne University of Technology, Centre for Astrophysics and Supercomputing, P.O. Box 218, Mail H30, Hawthorn, VIC 3122 (Australia)
  3. Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
  4. Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22365601
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 790; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; DISTRIBUTION; EVOLUTION; GALAXIES; GALAXY NUCLEI; MASS; STARS