The FUR to near-IR morphologies of luminous infrared galaxies in the goals sample

Journal Article · Mon Dec 01 00:00:00 EST 2014 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/148/6/111· OSTI ID:22342183

Petty, S. M. ^[1]; Armus, L.; Díaz-Santos, T.; Howell, J. H.; Surace, J. A. ^[2]; Charmandaris, V.; Psychogyios, A. ^[3]; Evans, A. S.; Stierwalt, S. ^[4]; Floc’h, E. Le ^[5]; Bridge, C. ^[6]; Inami, H. ^[7]

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1. Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States)
2. Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
3. Department of Physics, University of Crete, GR-71003, Heraklion (Greece)
4. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
5. CEA-Saclay, Orme des Merisiers, Bat. 709, F-91191 Gif-sur-Yvette (France)
6. Div. of Physics, Math and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
7. National Optical Astronomy Observatory, Tucson, AZ, 85719 (United States)

We compare the morphologies of a sample of 20 luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS) in the FUV, B, I, and H bands, using the Gini (G) and M{sub 20} parameters to quantitatively estimate the distribution and concentration of flux as a function of wavelength. Hubble Space Telescope (HST) images provide an average spatial resolution of ∼80 pc. While our LIRGs can be reliably classified as mergers across the entire range of wavelengths studied here, there is a clear shift toward more negative M{sub 20} (more bulge-dominated) and a less significant decrease in G values at longer wavelengths. We find no correlation between the derived FUV G-M{sub 20} parameters and the global measures of the IR to FUV flux ratio (IRX). Given the fine resolution in our HST data, this suggests either that the UV morphology and IRX are correlated on very small scales, or that the regions emitting the bulk of the IR emission emit almost no FUV light. We use our multi-wavelength data to simulate how merging LIRGs would appear from z∼0.5–3 in deep optical and near-infrared images such as the Hubble Ultra-Deep Field, and use these simulations to measure the G-M{sub 20} at these redshifts. Our simulations indicate a noticeable decrease in G, which flattens at z⩾2 by as much as 40%, resulting in mis-classifying our LIRGs as disk-like, even in the rest-frame FUV. The higher redshift values of M{sub 20} for the GOALS sources do not appear to change more than about 10% from the values at z∼0. The change in G-M{sub 20} is caused by the surface brightness dimming of extended tidal features and asymmetries, and also the decreased spatial resolution which reduced the number of individual clumps identified. This effect, seen as early as z∼0.5, could easily lead to an underestimate of the number of merging galaxies at high-redshift in the rest-frame FUV.

• OSTI ID: 22342183
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 148, Issue 6; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
ASYMMETRY
BRIGHTNESS
COMPARATIVE EVALUATIONS
CONCENTRATION RATIO
CORRELATIONS
DISTRIBUTION
EMISSION
FAR ULTRAVIOLET RADIATION
G VALUE
GALAXIES
NEAR INFRARED RADIATION
RED SHIFT
SIMULATION
SPACE
SPATIAL RESOLUTION
SURFACES
TELESCOPES
ULTRAVIOLET RADIATION
WAVELENGTHS