Hierarchical Formation in Action: Characterizing Accelerated Galaxy Evolution in Compact Groups Using Whole-Sky WISE Data
Abstract
Compact groups provide an environment to study the growth of galaxies amid multiple prolonged interactions. With their dense galaxy concentrations and relatively low velocity dispersions, compact groups mimic the conditions of hierarchical galaxy assembly. Compact group galaxies are known to show a bimodality in Spitzer IRAC infrared color space: galaxies are preferentially either quiescent with low specific star formation rates (SSFRs) or prolifically forming stars—galaxies with moderate levels of specific star formation are rare. Previous Spitzer IRAC studies identifying this "canyon" have been limited by small number statistics. We utilize whole-sky Wide-field Infrared Survey Explorer (WISE) data to study 163 compact groups, thereby tripling our previous sample and including more galaxies with intermediate mid-IR colors indicative of moderate SSFRs. We define a distinct WISE mid-IR color space (log[^(f12)_(f4.6)] versus log[^(f22)_(f3.4)]) that we use to identify canyon galaxies from the larger sample. We confirm that compact group galaxies show a bimodal distribution in the mid-infrared and identify 37 canyon galaxies with reliable photometry and intermediate mid-IR colors. Morphologically, we find that the canyon harbors a large population of both Sa–Sbc and E/S0 type galaxies, and that they fall on the optical red sequence rather than the green valley. Finally, we provide a catalog of WISE photometry for 567 of 652 galaxies selected from the sample of 163 compact groups.
Additional Information
© 2016. The American Astronomical Society. Received 2015 August 9; accepted 2016 March 3; published 2016 April 20. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS Web site is www.sdss.org. C.S.Z. would like to sincerely thank the anonymous referee for their thorough feedback throughout the review process. She would also like to thank the Virginia Space Grant Consortium and the University of Virginia College of Arts and Sciences for support. S.C.G. thanks the Natural Sciences and Engineering Research Council of Canada for support.Attached Files
Published - apj_821_2_113.pdf
Submitted - 1603.01623v1.pdf
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Additional details
- Eprint ID
- 68633
- Resolver ID
- CaltechAUTHORS:20160623-104838138
- NASA/JPL/Caltech
- Alfred P. Sloan Foundation
- Department of Energy (DOE)
- University of Utah
- Virginia Space Grant Consortium
- University of Virginia
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Created
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2016-06-23Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)