Access to Astronomical Catalogues

← Click to display the menu
J/ApJ/790/54    AGN models according to a UV to Mid-IR study      (Chung+, 2014)

A UV to Mid-IR study of AGN selection. Chung S.M., Kochanek C.S., Assef R., Brown M.J.I., Stern D., Jannuzi B.T., Gonzalez A.H., Hickox R.C., Moustakas J. <Astrophys. J., 790, 54 (2014)> =2014ApJ...790...54C (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Redshifts ; Models Keywords: galaxies: active - galaxies: distances and redshifts - quasars: general Abstract: We classify the spectral energy distributions (SEDs) of 431,038 sources in the 9 deg2 Bootes 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 Χ_ν2 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. Description: The data used in this work consist of the extensive multiwavelength imaging of the 9 deg2 NDWFS Bootes field and optical spectroscopy from AGES (Kochanek et al. 2012, J/ApJS/200/8) and R. C. Hickox et al. (2014, private communication). Data from NDWFS (BW, R, I, K) and NEWFIRM (J, H, Ks) are based on the Vega magnitude system, and data from GALEX, US, Y, and z bands are based on the AB system. All magnitudes reported throughout this paper are kept in their native zeropoint systems and refer to 6'' diameter aperture magnitudes unless otherwise stated. Objects were detected using SExtractor 2.3.3 (Bertin & Arnouts 1996A&AS..117..393B) run on the I-band images from the NDWFS third data release. To obtain consistent aperture photometry across the full Bootes field, the BW, R, I, Y, H, and KS images were smoothed to a common point spread function (PSF) of 1.35'' FWHM, while the US, z, and J images were smoothed to a common PSF of 1.60'' FWHM. We measured the aperture photometry for each object using our own code. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 142 431038 Model results
See also: J/ApJ/664/761 : BVRI photometry of AGNs in clusters (Martini+, 2007) J/ApJS/187/64 : The simultaneous optical-to-X-ray SED of AGNs (Grupe+, 2010) J/A+A/529/A135 : AGN Opt/IR properties in Lockman Hole (Rovilos+, 2011) J/AJ/144/11 : IR imaging, nuclear SEDs, Spitzer spectra of 22 AGNs (Mason+, 2012) J/ApJS/200/8 : AGES: the AGN and Galaxy Evolution Survey (Kochanek+, 2012) J/MNRAS/437/968 : AGN automatic photometric classification (Cavuoti+, 2014) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Aperture Right Ascension (J2000) 11- 18 F8.5 deg DEdeg Aperture Declination (J2000) 20- 25 F6.2 mag Imag I band 6'' diameter aperture magnitude 27- 30 F4.2 --- S SExtractor stellarity index (1 = point source) 32- 37 F6.2 --- zsp ?=-99.99 AGES spectroscopic redshift (1) 39- 42 A4 --- N Number of bands with detections/limits used in fits 44- 47 F4.2 --- z(G) Galaxy-only model photometric redshift 49- 54 F6.2 --- chi2(G) Galaxy-only model reduced Χ2 56- 61 F6.3 [10+10Lsun] L(Ell) Log elliptical galaxy component luminosity (2) 63- 68 F6.3 [10+10Lsun] L(Sbc) Log Sbc galaxy component luminosity (2) 70- 75 F6.3 [10+10Lsun] L(Irr) Log irregular galaxy component luminosity (2) 77- 80 F4.2 --- z(G+A) Galaxy + AGN model photometric redshift 82- 87 F6.2 --- chi2(G+A) Galaxy + AGN model reduced Χ2 89- 94 F6.3 [10+10Lsun] L(AGN+) Log Galaxy+AGN model AGN component luminosity (2) 96-101 F6.3 [10+10Lsun] L(Ell+) Log galaxy+AGN model elliptical galaxy component luminosity (2) 103-108 F6.3 [10+10Lsun] L(Sbc+) Log galaxy+AGN model Sbc galaxy component luminosity (2) 110-116 F7.3 [10+10Lsun] L(Irr+) Log galaxy+AGN model irregular galaxy component luminosity (2) 118-124 F7.2 --- F F-ratio value compared to Galaxy-only fit 126-129 F4.2 mag E(B-V) E(B-V) applied to AGN template 131-136 F6.2 --- chi2(S) Stellar model reduced Χ2 138-142 A5 --- SType Stellar type of best fit (3)
Note (1): -99.99 = AGES redshift not available. Note (2): Luminosities are calculated for the fit at the spectroscopic redshift if known. 0.0 = the best fit included no contribution from that template. Note (3): Where K/M means the best fit lay between the K and M stellar templates and 2000K means the best fit was the 2000K brown dwarf template. Uppercase letters refer to giant spectral templates and lowercase letters refer to dwarf spectral templates.
History: From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 17-Mar-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact