GOODS-HERSCHEL: IMPACT OF ACTIVE GALACTIC NUCLEI AND STAR FORMATION ACTIVITY ON INFRARED SPECTRAL ENERGY DISTRIBUTIONS AT HIGH REDSHIFT

Journal Article · Sat Nov 10 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/759/2/139· OSTI ID:22086374

Kirkpatrick, Allison; Pope, Alexandra ^[1]; Alexander, David M ^[2]; Charmandaris, Vassilis ^[3]; Daddi, Emmanuele; Elbaz, David; Gabor, Jared; Mullaney, James; Pannella, Maurilio; Aussel, Herve; Bournaud, Frederic; Dasyra, Kalliopi ^[4]; Dickinson, Mark ^[5]; Hwang, Ho Seong ^[6]; Ivison, Rob ^[7]; Scott, Douglas ^[8]; Altieri, Bruno; Coia, Daniela ^[9]; Buat, Veronique ^[10]; Dannerbauer, Helmut ^[11] ; others, and

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1. Department of Astronomy, University of Massachusetts, Amherst, MA 01002 (United States)
2. Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)
3. Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003, Heraklion (Greece)
4. Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)
5. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
6. Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
7. UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)
8. Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)
9. Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, E-28691 Madrid (Spain)
10. Laboratoire d'Astrophysique de Marseille (LAM), Universite d'Aix-Marseille, CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France)
11. Institut fuer Astrophysik, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180 Wien (Austria)

We explore the effects of active galactic nuclei (AGNs) and star formation activity on the infrared (0.3-1000 {mu}m) spectral energy distributions (SEDs) of luminous infrared galaxies from z = 0.5 to 4.0. We have compiled a large sample of 151 galaxies selected at 24 {mu}m (S {sub 24} {approx}> 100 {mu}Jy) in the GOODS-N and ECDFS fields for which we have deep Spitzer IRS spectroscopy, allowing us to decompose the mid-IR spectrum into contributions from star formation and AGN activity. A significant portion ({approx}25%) of our sample is dominated by an AGN (>50% of the mid-IR luminosity) in the mid-IR. Based on the mid-IR classification, we divide our full sample into four sub-samples: z {approx} 1 star-forming (SF) sources, z {approx} 2 SF sources, AGNs with clear 9.7 {mu}m silicate absorption, and AGNs with featureless mid-IR spectra. From our large spectroscopic sample and wealth of multi-wavelength data, including deep Herschel imaging at 100, 160, 250, 350, and 500 {mu}m, we use 95 galaxies with complete spectral coverage to create a composite SED for each sub-sample. We then fit a two-temperature component modified blackbody to the SEDs. We find that the IR SEDs have similar cold dust temperatures, regardless of the mid-IR power source, but display a marked difference in the warmer dust temperatures. We calculate the average effective temperature of the dust in each sub-sample and find a significant ({approx}20 K) difference between the SF and AGN systems. We compare our composite SEDs to local templates and find that local templates do not accurately reproduce the mid-IR features and dust temperatures of our high-redshift systems. High-redshift IR luminous galaxies contain significantly more cool dust than their local counterparts. We find that a full suite of photometry spanning the IR peak is necessary to accurately account for the dominant dust temperature components in high-redshift IR luminous galaxies.

• OSTI ID: 22086374
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 759; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ABSORPTION SPECTROSCOPY
ASTRONOMY
ASTROPHYSICS
COMPARATIVE EVALUATIONS
COSMIC DUST
COSMOLOGY
ENERGY SPECTRA
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
INFRARED SPECTRA
LUMINOSITY
PHOTOMETRY
RED SHIFT
SILICATES
STARS