Spitzer power-law active galactic nucleus candidates in the Chandra Deep Field-North

J. L. Donley, George H. Rieke, P. G. Pérez-González, J. R. Rigby, A. Alonso-Herrero

Research output: Contribution to journalArticle

141 Citations (Scopus)

Abstract

We define a sample of 62 galaxies in the Chandra Deep Field-North whose Spitzer IRAC SEDs exhibit the characteristic power-law emission expected of luminous AGNs. We study the multiwavelength properties of this sample and compare the AGNs selected in this way to those selected via other Spitzer color-color criteria. Only 55% of the power-law galaxies are detected in the X-ray catalog at exposures of >0.5 Ms, although a search for faint emission results in the detection of 85% of the power-law galaxies at the ≥2.5 σ detection level. Most of the remaining galaxies are likely to host AGNs that are heavily obscured in the X-ray. Because the power-law selection requires the AGNs to be energetically dominant in the near- and mid-infrared, the power-law galaxies comprise a significant fraction of the S/Hfeer-detected AGN population at high luminosities and redshifts. The high 24 μm detection fraction also points to a luminous population. The power-law galaxies comprise a subset of color-selected AGN candidates. A comparison with various mid-infrared color selection criteria demonstrates that while the color-selected samples contain a larger fraction of the X-ray-luminous AGNs, there is evidence that these selection techniques also suffer from a higher degree of contamination by star-forming galaxies in the deepest exposures. Considering only those power-law galaxies detected in the X-ray catalog, we derive an obscured fraction of 68% (2:1). Including all of the power-law galaxies suggests an obscured fraction of <81% (4:1).

Original languageEnglish (US)
Pages (from-to)167-190
Number of pages24
JournalAstrophysical Journal
Volume660
Issue number1 I
DOIs
StatePublished - May 1 2007

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active galactic nuclei
power law
galaxies
color
catalogs
x rays
set theory
contamination
luminosity
stars
detection

Keywords

  • Galaxies: active
  • Infrared: galaxies
  • X-rays: galaxies

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Donley, J. L., Rieke, G. H., Pérez-González, P. G., Rigby, J. R., & Alonso-Herrero, A. (2007). Spitzer power-law active galactic nucleus candidates in the Chandra Deep Field-North. Astrophysical Journal, 660(1 I), 167-190. https://doi.org/10.1086/512798

Spitzer power-law active galactic nucleus candidates in the Chandra Deep Field-North. / Donley, J. L.; Rieke, George H.; Pérez-González, P. G.; Rigby, J. R.; Alonso-Herrero, A.

In: Astrophysical Journal, Vol. 660, No. 1 I, 01.05.2007, p. 167-190.

Research output: Contribution to journalArticle

Donley, JL, Rieke, GH, Pérez-González, PG, Rigby, JR & Alonso-Herrero, A 2007, 'Spitzer power-law active galactic nucleus candidates in the Chandra Deep Field-North', Astrophysical Journal, vol. 660, no. 1 I, pp. 167-190. https://doi.org/10.1086/512798
Donley, J. L. ; Rieke, George H. ; Pérez-González, P. G. ; Rigby, J. R. ; Alonso-Herrero, A. / Spitzer power-law active galactic nucleus candidates in the Chandra Deep Field-North. In: Astrophysical Journal. 2007 ; Vol. 660, No. 1 I. pp. 167-190.
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