CHANSEXAGN ivo://nasa.heasarc/chansexagn NASA/GSFC HEASARC Eckart et al. 2026-10-02 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The authors compare the relative merits of active galactic nuclei (AGN) selection at X-ray and mid-infrared wavelengths using data from moderately deep fields observed by both Chandra and Spitzer. The X-ray-selected AGN sample and associated photometric and spectroscopic optical follow-up are drawn from a subset of fields studied as part of the Serendipitous Extragalactic X-ray Source Identification (SEXSI) program. Mid-infrared data in these fields are derived from targeted and archival Spitzer imaging, and mid-infrared AGN selection is accomplished primarily through application of the Infrared Array Camera (IRAC) color-color AGN "wedge" selection technique. Nearly all X-ray sources in these fields which exhibit clear spectroscopic signatures of AGN activity have mid-infrared colors consistent with IRAC AGN selection. These are predominantly the most luminous X-ray sources. X-ray sources that lack high-ionization and/or broad lines in their optical spectra are far less likely to be selected as AGNs by mid-infrared color selection techniques. The fraction of X-ray sources identified as AGN in the mid-infrared increases monotonically as the X-ray luminosity increases. Conversely, only 22% of mid-infrared-selected AGN are detected at X-ray energies in the moderately deep (t_exp_n~ 100 ks) SEXSI Chandra data. The authors have expanded the multi-wavelength data available for six SEXSI fields by obtaining Spitzer imaging observations. All six fields have deep Chandra X-ray images, optical imaging, and extensive, deep optical spectroscopy -- all of which has been published in Harrison et al. (2003, ApJ, 596, 944), Eckart et al. (2005, ApJS, 156, 35), and Eckart et al. (2006, ApJS, 165, 19). The authors obtained mid-infrared imaging through both archival and targeted Spitzer programs which include imaging at 3.6, 4.5, 5.8, and 8 micron (µm) from IRAC (PID 00017, 00064, 20694 and 20808), and imaging at 24 um from MIPS (PID 20808 and 00083). This table contains mid-IR photometric data for 290 hard X-ray-selected SEXSI sources. Each of the four IRAC catalogs as well as the MIPS catalog was individually matched to the SEXSI X-ray source positions using a 2.5 arcseconds search radius. To calculate a false match rate, the authors shifted the X-ray source catalog by 1' and matched to the IRAC and MIPS catalogs; this entire procedure was repeated 6 times using different 1' shifts. The resulting false match rates were 10.1% (3.6 um), 7.2% (4.5 um), 3.7% (5.8 um), 2.6% (8.0 um), 1% (24 um), and <1% for four-band-detected IRAC sources. This table was created by the HEASARC in Match 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/708/584">CDS Catalog J/ApJ/708/584</a> file table2.dat. This is a service provided by NASA HEASARC . 2010ApJ...708..584E https://heasarc.gsfc.nasa.gov/W3Browse/all/chansexagn.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=chansexagn& GET text/xml 180 99999 true 341.82266667 3.54147222 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=chansexagn GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_chansexagn&Action=More+Options&Action=Parameter+Search&ConeAdd=1 SPITZER 0.0166666666666667 Infrared X-ray public chansexagn Chandra Serendipitous Extragalactic X-Ray Source ID (SEXSI)/Spit name Source Designation (CXOSEXSI JHHMMSS.s+DDMMSS) meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable hb_flux Galactic-Absorption-Adjusted 2-10keV Flux erg/s/cm^2 phot.flux;em.X-ray.medium double nullable log_hb_lx Logarithm of 2-10keV Luminosity in erg/s log(erg/s) phys.luminosity;em.X-ray.medium double nullable redshift Redshift src.redshift double nullable object_type Classification of Object src.class char nullable irac_3p6_um_flux Flux in the Spitzer/IRAC 3.6um Image microJy phot.flux.density;em.IR.3-4um double nullable irac_3p6_um_flux_error Error in the Flux in the Spitzer/IRAC 3.6um Image microJy stat.error;phot.flux.density;em.IR.3-4um double nullable irac_3p6_um_flux_flag Flag [0,7] for the Flux in the Spitzer/IRAC 3.6um Image meta.code;phot.flux.density;em.IR.3-4um short nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable offset_dec Corrected X-Ray/Spitzer Declination Position Difference arcsec pos.angDistance;em.X-ray;em.IR double nullable rmag_flag Flag [1,6] Indicates Optical Identification meta.code;phot.mag;em.opt.R short nullable offset_ra Corrected X-Ray/Spitzer Right Ascension Position Difference arcsec pos.angDistance;em.X-ray;em.IR double nullable hardness_ratio Hardness Ratio phot.flux;arith.ratio;em.X-ray double nullable bii Galactic Latitude degree pos.galactic.lat double nullable rmag The R-Band Magnitude mag phot.mag;em.opt.R double nullable lii Galactic Longitude degree pos.galactic.lon double nullable mips_24_um_flux_flag Flag [0,8] for the Flux in the Spitzer/MIPS 24um Image meta.code;phot.flux.density;em.IR.15-30um short nullable irac_8p0_um_flux_flag Flag [0,8] for the Flux in the Spitzer/IRAC 8.0um Image meta.code;phot.flux.density;em.IR.4-8um short nullable irac_5p8_um_flux_flag Flag [0,8] for the Flux in the Spitzer/IRAC 5.6um Image meta.code;phot.flux.density;em.IR.4-8um short nullable class Browse Object Classification src.class short nullable irac_5p8_um_flux_error Error in the Flux in the Spitzer/IRAC 5.6um Image microJy stat.error;phot.flux.density;em.IR.4-8um double nullable mips_24_um_flux Flux in the Spitzer/MIPS 24um Image microJy phot.flux.density;em.IR.15-30um double nullable irac_4p5_um_flux_error Error in the Flux in the Spitzer/IRAC 4.5um Image microJy stat.error;phot.flux.density;em.IR.4-8um double nullable irac_5p8_um_flux Flux in the Spitzer/IRAC 5.6um Image microJy phot.flux.density;em.IR.4-8um double nullable rmag_limit Limit Flag for the R-Band Magnitude meta.code;phot.mag;em.opt.R char nullable irac_4p5_um_flux_flag Flag [0,7] for the Flux in the Spitzer/IRAC 4.5um Image meta.code;phot.flux.density;em.IR.4-8um short nullable log_hb_over_opt_flux Logarithm of Hard-Band Flux (2-10keV) to Optical Flux Ratio phot.flux;arith.ratio double nullable irac_8p0_um_flux Flux in the Spitzer/IRAC 8.0um Image microJy phot.flux.density;em.IR.4-8um double nullable log_nh Logarithm of H Column Density log(cm^-2) phys.columnDensity;stat.fit double nullable mips_24_um_flux_error Error in the Flux in the Spitzer/MIPS 24um Image microJy stat.error;phot.flux.density;em.IR.15-30um double nullable irac_8p0_um_flux_error Error in the Flux in the Spitzer/IRAC 8.0um Image microJy stat.error;phot.flux.density;em.IR.4-8um double nullable irac_4p5_um_flux Flux in the Spitzer/IRAC 4.5um Image microJy phot.flux.density;em.IR.4-8um double nullable