Morphology and Molecular Gas Fractions of Local Luminous Infrared Galaxies as a Function of Infrared Luminosity and Merger Stage
Abstract
We present a new, detailed analysis of the morphologies and molecular gas fractions (MGFs) for a complete sample of 65 local luminous infrared galaxies from Great Observatories All-Sky Luminous Infrared Galaxies (LIRG) Survey using high resolution I-band images from The Hubble Space Telescope, the University of Hawaii 2.2 m Telescope and the Pan-STARRS1 Survey. Our classification scheme includes single undisturbed galaxies, minor mergers, and major mergers, with the latter divided into five distinct stages from pre-first pericenter passage to final nuclear coalescence. We find that major mergers of molecular gas-rich spirals clearly play a major role for all sources with L_(IR) > 10^(11.5) L_☉ however, below this luminosity threshold, minor mergers and secular processes dominate. Additionally, galaxies do not reach L_(IR) > 10^(12.0 L_☉ until late in the merger process when both disks are near final coalescence. The mean MGF (MGF = M_(H_2/M_* + M_(H_2) for non-interacting and early-stage major merger LIRGs is 18 ± 2%, which increases to 33 ± 3%, for intermediate stage major merger LIRGs, consistent with the hypothesis that, during the early-mid stages of major mergers, most of the initial large reservoir of atomic gas (HI) at large galactocentric radii is swept inward where it is converted into molecular gas (H_2).
Additional Information
© 2016 The American Astronomical Society. Received 2015 June 24; accepted 2016 April 4; published 2016 July 12. D.S. acknowledges the hospitality of the Aspen Center for Physics, which is supported by the National Science Foundation Grant No. PHY-1066293. D.S. and K.L. also acknowledge the Distinguished Visitor Program at the Research School for Astronomy and Astrophysics, Australian National University for their generous support while they were in residence at the Mount Stromlo Observatory, Weston Creek, NSW. K.L., D.S., and J.B. gratefully acknowledge funding support from NASA grant NNX11AB02G. V.U. wishes to acknowledge partial funding support from the Thirty Meter Telescope International Observatory and the UC Chancellor's Postdoctoral Fellowship Program. A.S.E., D.C.K., and G.C.P. were supported by NASA grant HST-GO10592.01-A and by the NSF grant AST 1109475. A.S.E. was also supported by the Taiwan, R.O.C. Ministry of Science and Technology grant MoST 102-2119-M-001-MY3. G.C.P. acknowledges support from a FONDECYT Postdoctoral Fellowship (No. 3150361). V.U. and C.I. extend appreciation toward the UH TAC for their generous support of this project in awarding telescope time on Maunakea, as well as Colin Aspin and the UH 2.2 m Telescope staff for their help and support in the acquisition of the ground-based imaging and optical photometry. This research has made use of the NASA/IPAC Extragalactic Database (NED) and the IPAC Science Archive, which are operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The HST-GOALS survey includes observations taken with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc, under NASA contract NAS 5-2655. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen's University Belfast, the Harvard–Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE), and the Los Alamos National Laboratory.Attached Files
Published - apj_825_2_128.pdf
Submitted - 1605.05417v1.pdf
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Additional details
- Eprint ID
- 70418
- Resolver ID
- CaltechAUTHORS:20160919-093556831
- NSF
- PHY-1066293
- Australian National University
- NASA
- NNX11AB02G
- Thirty Meter Telescope International Observatory
- UC Chancellor's Postdoctoral Fellowship
- NASA
- HST-GO10592.01-A
- NSF
- AST 1109475
- Ministry of Science and Technology (Taipei)
- 102-2119-M-001-MY3
- Fondo Nacional de Desarrollo Científico y Tecnolόgico (FONDECYT)
- 3150361
- NASA/JPL/Caltech
- NASA
- NAS 5-26555
- NASA
- NNX08AR22G
- NSF
- AST-1238877
- University of Maryland
- Eotvos Lorand University (ELTE)
- Los Alamos National Laboratory
- Created
-
2016-09-19Created from EPrint's datestamp field
- Updated
-
2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)