Morphology and molecular gas fractions of local luminous infrared galaxies as a function of infrared luminosity and merger stage

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 U...

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Detalles Bibliográficos
Autores principales: Larson, K.L., Sanders, D.B., Barnes, J.E., Ishida, C.M., Evans, A.S., Mazzarella, J.M., Kim, D.-C., Privon, G.C., Mirabel, I.F., Flewelling, H.A.
Formato: JOUR
Materias:
galaxies: evolution
galaxies: interactions
infrared: galaxies
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0004637X_v825_n2_p_Larson
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario: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 H2 /(M ∗ +M H2 )) 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 ). © 2016. The American Astronomical Society. All rights reserved.

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