skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A JOINT MODEL OF THE X-RAY AND INFRARED EXTRAGALACTIC BACKGROUNDS. I. MODEL CONSTRUCTION AND FIRST RESULTS

Abstract

We present an extragalactic population model of the cosmic background light to interpret the rich high-quality survey data in the X-ray and IR bands. The model incorporates star formation and supermassive black hole (SMBH) accretion in a co-evolution scenario to fit simultaneously 617 data points of number counts, redshift distributions, and local luminosity functions (LFs) with 19 free parameters. The model has four main components, the total IR LF, the SMBH accretion energy fraction in the IR band, the star formation spectral energy distribution (SED), and the unobscured SMBH SED extinguished with a H I column density distribution. As a result of the observational uncertainties about the star formation and SMBH SEDs, we present several variants of the model. The best-fit reduced {chi}{sup 2} reaches as small as 2.7-2.9 of which a significant amount (>0.8) is contributed by cosmic variances or caveats associated with data. Compared to previous models, the unique result of this model is to constrain the SMBH energy fraction in the IR band that is found to increase with the IR luminosity but decrease with redshift up to z {approx} 1.5; this result is separately verified using aromatic feature equivalent-width data. The joint modeling of X-ray andmore » mid-IR data allows for improved constraints on the obscured active galactic nucleus (AGN), especially the Compton-thick AGN population. All variants of the model require that Compton-thick AGN fractions decrease with the SMBH luminosity but increase with redshift while the type 1 AGN fraction has the reverse trend.« less

Authors:
; ; ;  [1];  [2]
  1. Infrared Processing and Analysis Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  2. Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States)
Publication Date:
OSTI Identifier:
22167838
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 764; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; COMPARATIVE EVALUATIONS; DENSITY; DISTRIBUTION; ENERGY SPECTRA; GALACTIC EVOLUTION; GALAXIES; LUMINOSITY; NUCLEI; RED SHIFT; SIMULATION; X RADIATION

Citation Formats

Shi, Yong, Helou, George, Armus, Lee, Stierwalt, Sabrina, and Dale, Daniel. A JOINT MODEL OF THE X-RAY AND INFRARED EXTRAGALACTIC BACKGROUNDS. I. MODEL CONSTRUCTION AND FIRST RESULTS. United States: N. p., 2013. Web. doi:10.1088/0004-637X/764/1/28.
Shi, Yong, Helou, George, Armus, Lee, Stierwalt, Sabrina, & Dale, Daniel. A JOINT MODEL OF THE X-RAY AND INFRARED EXTRAGALACTIC BACKGROUNDS. I. MODEL CONSTRUCTION AND FIRST RESULTS. United States. https://doi.org/10.1088/0004-637X/764/1/28
Shi, Yong, Helou, George, Armus, Lee, Stierwalt, Sabrina, and Dale, Daniel. 2013. "A JOINT MODEL OF THE X-RAY AND INFRARED EXTRAGALACTIC BACKGROUNDS. I. MODEL CONSTRUCTION AND FIRST RESULTS". United States. https://doi.org/10.1088/0004-637X/764/1/28.
@article{osti_22167838,
title = {A JOINT MODEL OF THE X-RAY AND INFRARED EXTRAGALACTIC BACKGROUNDS. I. MODEL CONSTRUCTION AND FIRST RESULTS},
author = {Shi, Yong and Helou, George and Armus, Lee and Stierwalt, Sabrina and Dale, Daniel},
abstractNote = {We present an extragalactic population model of the cosmic background light to interpret the rich high-quality survey data in the X-ray and IR bands. The model incorporates star formation and supermassive black hole (SMBH) accretion in a co-evolution scenario to fit simultaneously 617 data points of number counts, redshift distributions, and local luminosity functions (LFs) with 19 free parameters. The model has four main components, the total IR LF, the SMBH accretion energy fraction in the IR band, the star formation spectral energy distribution (SED), and the unobscured SMBH SED extinguished with a H I column density distribution. As a result of the observational uncertainties about the star formation and SMBH SEDs, we present several variants of the model. The best-fit reduced {chi}{sup 2} reaches as small as 2.7-2.9 of which a significant amount (>0.8) is contributed by cosmic variances or caveats associated with data. Compared to previous models, the unique result of this model is to constrain the SMBH energy fraction in the IR band that is found to increase with the IR luminosity but decrease with redshift up to z {approx} 1.5; this result is separately verified using aromatic feature equivalent-width data. The joint modeling of X-ray and mid-IR data allows for improved constraints on the obscured active galactic nucleus (AGN), especially the Compton-thick AGN population. All variants of the model require that Compton-thick AGN fractions decrease with the SMBH luminosity but increase with redshift while the type 1 AGN fraction has the reverse trend.},
doi = {10.1088/0004-637X/764/1/28},
url = {https://www.osti.gov/biblio/22167838}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 764,
place = {United States},
year = {Sun Feb 10 00:00:00 EST 2013},
month = {Sun Feb 10 00:00:00 EST 2013}
}