A UV to mid-IR study of AGN selection

Sun Mi Chung, Christopher S. Kochanek, Roberto Assef, Michael J I Brown, Daniel Stern, Buell Tomasson Jannuzi, Anthony H. Gonzalez, Ryan C. Hickox, John Moustakas

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We classify the spectral energy distributions (SEDs) of 431,038 sources in the 9 deg2 Boötes field of the NOAO Deep Wide-Field Survey (NDWFS). There are up to 17 bands of data available per source, including ultraviolet (GALEX), optical (NDWFS), near-IR (NEWFIRM), and mid-infrared (IRAC and MIPS) data, as well as spectroscopic redshifts for 20,000 objects, primarily from the AGN and Galaxy Evolution Survey. We fit galaxy, active galactic nucleus (AGN), stellar, and brown dwarf templates to the observed SEDs, which yield spectral classes for the Galactic sources and photometric redshifts and galaxy/AGN luminosities for the extragalactic sources. The photometric redshift precision of the galaxy and AGN samples are σ/(1 + z) = 0.040 and σ/(1 + z) = 0.169, respectively, with the worst 5% outliers excluded. On the basis of the of the SED fit for each SED model, we are able to distinguish between Galactic and extragalactic sources for sources brighter than I = 23.5 mag. We compare the SED fits for a galaxy-only model and a galaxy-AGN model. Using known X-ray and spectroscopic AGN samples, we confirm that SED fitting can be successfully used as a method to identify large populations of AGNs, including spatially resolved AGNs with significant contributions from the host galaxy and objects with the emission line ratios of "composite" spectra. We also use our results to compare with the X-ray, mid-IR, optical color, and emission line ratio selection techniques. For an F-ratio threshold of F > 10, we find 16,266 AGN candidates brighter than I = 23.5 mag and a surface density of 1900 AGN deg-2.

Original languageEnglish (US)
Article number54
JournalAstrophysical Journal
Volume790
Issue number1
DOIs
StatePublished - Jul 20 2014

Fingerprint

active galactic nuclei
spectral energy distribution
galaxies
energy
field survey
outlier
distribution
x rays
templates
luminosity
color
composite materials
thresholds

Keywords

  • galaxies: active
  • galaxies: distances and redshifts
  • quasars: general

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Chung, S. M., Kochanek, C. S., Assef, R., Brown, M. J. I., Stern, D., Jannuzi, B. T., ... Moustakas, J. (2014). A UV to mid-IR study of AGN selection. Astrophysical Journal, 790(1), [54]. https://doi.org/10.1088/0004-637X/790/1/54

A UV to mid-IR study of AGN selection. / Chung, Sun Mi; Kochanek, Christopher S.; Assef, Roberto; Brown, Michael J I; Stern, Daniel; Jannuzi, Buell Tomasson; Gonzalez, Anthony H.; Hickox, Ryan C.; Moustakas, John.

In: Astrophysical Journal, Vol. 790, No. 1, 54, 20.07.2014.

Research output: Contribution to journalArticle

Chung, SM, Kochanek, CS, Assef, R, Brown, MJI, Stern, D, Jannuzi, BT, Gonzalez, AH, Hickox, RC & Moustakas, J 2014, 'A UV to mid-IR study of AGN selection', Astrophysical Journal, vol. 790, no. 1, 54. https://doi.org/10.1088/0004-637X/790/1/54
Chung SM, Kochanek CS, Assef R, Brown MJI, Stern D, Jannuzi BT et al. A UV to mid-IR study of AGN selection. Astrophysical Journal. 2014 Jul 20;790(1). 54. https://doi.org/10.1088/0004-637X/790/1/54
Chung, Sun Mi ; Kochanek, Christopher S. ; Assef, Roberto ; Brown, Michael J I ; Stern, Daniel ; Jannuzi, Buell Tomasson ; Gonzalez, Anthony H. ; Hickox, Ryan C. ; Moustakas, John. / A UV to mid-IR study of AGN selection. In: Astrophysical Journal. 2014 ; Vol. 790, No. 1.
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