A FAR-INFRARED CHARACTERIZATION OF 24 {mu}m SELECTED GALAXIES AT 0 < z < 2.5 USING STACKING AT 70 {mu}m AND 160 {mu}m IN THE COSMOS FIELD

Journal Article · Thu Jul 01 00:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/717/1/175· OSTI ID:21452884

Lee, Nicholas; Le Floc'h, Emeric; Sanders, D B ^[1]; Frayer, D T ^[2]; Arnouts, Stephane ^[3]; Ilbert, Olivier ^[4]; Aussel, Herve ^[5]; Salvato, Mara; Scoville, N Z ^[6]; Kartaltepe, Jeyhan S ^[7]

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1. Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)
2. Infrared Processing and Analysis Center, California Institute of Technology 100-22, Pasadena, CA 91125 (United States)
3. Canada France Hawaii Telescope Corporation, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743 (United States)
4. Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12 (France)
5. UMR AIM (CEA-UP7-CNRS), CEA-Saclay, Orme des Merisiers, bat. 709, F-91191 Gif-sur-Yvette Cedex (France)
6. California institute of Technology, MS 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
7. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

We present a study of the average properties of luminous infrared galaxies detected directly at 24 {mu}m in the COSMOS field using a median stacking analysis at 70 {mu}m and 160 {mu}m. Over 35,000 sources spanning 0 {<=} z {<=} 3 and 0.06 mJy {<=}S{sub 24} {<=} 3.0 mJy are stacked, divided into bins of both photometric redshift and 24 {mu}m flux. We find no correlation of S{sub 70}/S{sub 24} flux density ratio with S{sub 24}, but find that galaxies with higher S{sub 24} have a lower S{sub 160}/S{sub 24} flux density ratio. These observed ratios suggest that 24 {mu}m selected galaxies have warmer spectral energy distributions (SEDs) at higher mid-IR fluxes, and therefore have a possible higher fraction of active galactic nuclei. Comparisons of the average S{sub 70}/S{sub 24} and S{sub 160}/S{sub 24} colors with various empirical templates and theoretical models show that the galaxies detected at 24 {mu}m are consistent with 'normal' star-forming galaxies and warm mid-IR galaxies such as Mrk 231, but inconsistent with heavily obscured galaxies such as Arp 220. We perform a {chi}{sup 2} analysis to determine best-fit galactic model SEDs and total IR luminosities for each of our bins. We compare our results to previous methods of estimating L{sub IR} and find that previous methods show considerable agreement over the full redshift range, except for the brightest S{sub 24} sources, where they overpredict the bolometric IR luminosity at high redshift, most likely due to their warmer dust SED. We present a table that can be used as a more accurate and robust method for estimating bolometric infrared luminosity from 24 {mu}m flux densities.

• OSTI ID: 21452884
• Journal Information: Astrophysical Journal, Vol. 717, Issue 1; Other Information: DOI: 10.1088/0004-637X/717/1/175; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BOLOMETERS
DUSTS
ENERGY SPECTRA
FLUX DENSITY
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
LUMINOSITY
RED SHIFT
STARS
UNIVERSE
EVOLUTION
MEASURING INSTRUMENTS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SPECTRA