THE NUCLEAR STRUCTURE IN NEARBY LUMINOUS INFRARED GALAXIES: HUBBLE SPACE TELESCOPE NICMOS IMAGING OF THE GOALS SAMPLE

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/141/3/100· OSTI ID:21583192

Haan, S; Surace, J A; Armus, L; Howell, J H; Inami, H; Petric, A; Murphy, E J; Stierwalt, S ^[1]; Evans, A S; Kim, D C ^[2]; Mazzarella, J M ^[3]; Vavilkin, T ^[4]; Sanders, D B; U, V ^[5]; Bridge, C R; Melbourne, J L ^[6]; Charmandaris, V; Diaz-Santos, T ^[7]; Marshall, J A ^[8]

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1. Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
2. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
3. Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
4. Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794 (United States)
5. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
6. California Institute of Technology, Pasadena, CA 91125 (United States)
7. Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003, Heraklion (Greece)
8. The Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

We present results of Hubble Space Telescope (HST) NICMOS H-band imaging of 73 of the most luminous (i.e., log[L{sub IR}/L{sub sun}]>11.4) infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey. This data set combines multi-wavelength imaging and spectroscopic data from space-based (Spitzer, HST, GALEX, and Chandra) and ground-based telescopes. In this paper, we use high-resolution near-infrared data to recover nuclear structure that is obscured by dust at optical wavelengths and measure the evolution in this structure along the merger sequence. A large fraction of all galaxies in our sample possess double nuclei ({approx}63%) or show evidence for triple nuclei ({approx}6%). Half of these double nuclei are not visible in the HST B-band images due to dust obscuration. The majority of interacting LIRGs have remaining merger timescales of 0.3-1.3 Gyr, based on the projected nuclear separations and the mass ratio of nuclei. We find that the bulge luminosity surface density L{sub Bulge}/R{sup 2}{sub Bulge} increases significantly along the merger sequence (primarily due to a decrease of the bulge radius), while the bulge luminosity shows a small increase toward late merger stages. No significant increase of the bulge Sersic index is found. LIRGs that show no interaction features have on average a significantly larger bulge luminosity, suggesting that non-merging LIRGs have larger bulge masses than merging LIRGs. This may be related to the flux-limited nature of the sample and the fact that mergers can significantly boost the IR luminosity of otherwise low luminosity galaxies. We find that the projected nuclear separation is significantly smaller for ULIRGs (median value of 1.2 kpc) than for LIRGs (median value of 6.7 kpc), suggesting that the LIRG phase appears earlier in mergers than the ULIRG phase.

• OSTI ID: 21583192
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 141, Issue 3; Other Information: DOI: 10.1088/0004-6256/141/3/100; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DUSTS
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
IMAGES
LUMINOSITY
MASS
TELESCOPES
EVOLUTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES