Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:astro-ph/0604429)
· References in the article
· Citations to the Article (4) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (3)
· NED Objects (34)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Parametric Modeling of the 3.6-8 μm Color Distributions of Galaxies in the SWIRE Survey
Authors:
Davoodi, Payam; Oliver, Seb; Polletta, Maria del Carmen; Rowan-Robinson, Michael; Savage, Richard S.; Waddington, Ian; Farrah, Duncan; Babbedge, Tom; Lonsdale, Carol; Evans, Tracey; Fang, Fan; Gonzalez-Solares, Eduardo; Jarrett, Tom; Shupe, David L.; Siana, Brian; Smith, Harding E.; Surace, Jason; Xu, C. Kevin
Affiliation:
AA(Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK.), AB(Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK.), AC(Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, CA 92093-0424.), AD(Astrophysics Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW, UK.), AE(Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK.), AF(Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK.), AG(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AH(Astrophysics Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW, UK.), AI(Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, CA 92093-0424.; Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AJ(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AK(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AL(University of Cambridge, Institute of Astronomy, The Observatories, Madingley Road, Cambridge CB3 0HA, UK.), AM(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AN(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AO(Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, CA 92093-0424.), AP(Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, CA 92093-0424.), AQ(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.), AR(Infrared Processing and Analysis Center, California Institute of Technology, 100-22, Pasadena, CA 91125.)
Publication:
The Astronomical Journal, Volume 132, Issue 5, pp. 1818-1833. (AJ Homepage)
Publication Date:
11/2006
Origin:
UCP
AJ Keywords:
Galaxies: Fundamental Parameters, Infrared: Galaxies, Methods: Statistical
DOI:
10.1086/506385
Bibliographic Code:
2006AJ....132.1818D

Abstract

We fit a parametric model comprising a mixture of multidimensional Gaussian functions to the 3.6-8 μm color and optical photometric redshift distribution of galaxy populations in the ELAIS-N1 and Lockman Fields of the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Legacy survey. For 16,698 sources in ELAIS-N1 we find our data are best modeled (in the sense of the Bayesian information criterion) by the sum of four Gaussian distributions or modes (Ca, Cb, Cc, and Cd). We compare the fit of our empirical model with predictions from existing semianalytic and phenomenological models. We infer that our empirical model provides a better description of the mid-infrared color distribution of the SWIRE survey than these existing models. This color distribution test is thus a powerful model discriminator and is entirely complementary to comparisons of number counts. We use our model to provide a galaxy classification scheme and explore the nature of the galaxies in the different modes of the model. Population Ca is found to consist of dusty star-forming systems such as ultraluminous infrared galaxies, over a broad redshift range. Low-redshift late-type spiral galaxies are found in population Cb, in which polycyclic aromatic hydrocarbon emission dominates at 8 μm, making these sources very red in longer wavelength Infrared Array Camera (IRAC) colors. Population Cc consists of dusty starburst systems with high levels of star formation activity at intermediate redshifts. Low-redshift early-type spiral and elliptical galaxies are found to dominate population Cd. We thus find a greater variety of galaxy types than one can with optical photometry alone. Finally, we develop a new technique to identify unusual objects and find a selection of outliers with very red IRAC colors. These objects are not detected in the optical but have very strong detections in the mid-infrared. These sources are modeled as dust-enshrouded, strongly obscured active galactic nuclei (AGNs), for which the high mid-infrared emission may be attributed to either dust heated by the AGNs or substantial star formation. These sources have zph~2-4, making them incredibly infrared-luminous, with LIR~1012.6-1014.1 Lsolar.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints