J/ApJ/877/5ivo://CDS.VizieR/J/ApJ/877/5doi:10.26093/cds/vizier.18770005CDSLi J.Xue Y.Sun M.Liu T.Vito F.Brandt W.N.Hughes T.M.Yang G.,Tozzi P.Zhu S.Zheng X.Luo B.Chen C.-T.Vignali C.Gilli R.Shu X.2022-04-04T08:59:18Z2020-12-10T13:24:46ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fractive-galactic-nucleix-ray-sourcesredshiftedWe present a detailed X-ray spectral analysis of 1152 active galactic nuclei (AGNs) selected in the Chandra Deep Fields (CDFs), in order to identify highly obscured AGNs (N_H_>10^23^cm^-2^). By fitting spectra with physical models, 436 (38%) sources with L_X_>10^42^erg/s are confirmed to be highly obscured, including 102 Compton-thick (CT) candidates. We propose a new hardness ratio measure of the obscuration level that can be used to select highly obscured AGN candidates. The completeness and accuracy of applying this method to our AGNs are 88% and 80%, respectively. The observed log N-log S relation favors cosmic X-ray background models that predict moderate (i.e., between optimistic and pessimistic) CT number counts. Nineteen percent (6/31) of our highly obscured AGNs that have optical classifications are labeled as broad-line AGNs, suggesting that, at least for part of the AGN population, the heavy X-ray obscuration is largely a line-of-sight effect, i.e., some high column density clouds on various scales (but not necessarily a dust-enshrouded torus) along our sight line may obscure the compact X-ray emitter. After correcting for several observational biases, we obtain the intrinsic N_H_ distribution and its evolution. The CT/highly obscured fraction is roughly 52% and is consistent with no evident redshift evolution. We also perform long-term (~17yr in the observed frame) variability analyses for 31 sources with the largest number of counts available. Among them, 17 sources show flux variabilities: 31% (5/17) are caused by the change of N_H_, 53% (9/17) are caused by the intrinsic luminosity variability, 6% (1/17) are driven by both effects, and 2 are not classified owing to large spectral fitting errors.2019ApJ...877....5Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/877/5CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)VIII/10 : Bell Laboratories H I Profiles (Stark+ 1992)VIII/28 : Bell Laboratories H I Survey (Stark+ 1992)J/ApJS/79/77 : Bell Lab. H I Survey - High Velocity Clouds (Stark+ 1992)J/AJ/126/539 : The Chandra Deep Fields North and South (Alexander+, 2003)J/A+A/409/79 : HELLAS2XMM survey. IV. (Fiore+, 2003)J/ApJS/155/73 : Phot. redshifts of X-ray sources in CDF-S (Zheng+, 2004)J/A+A/451/457 : X-ray properties of AGN in CDFS (Tozzi+, 2006)J/ApJ/642/673 : IR-selected obscured AGN candidates (Polletta+, 2006)J/ApJ/660/167 : Spitzer AGN candidates in CDFN (Donley+, 2007)J/A+A/488/73 : Variability-selected AGN in Chandra DFS (Trevese+, 2008)J/A+A/497/81 : Variability-selected AGN in CDFS (Boutsia+, 2009)J/ApJ/693/1713 : Spectroscopy of X-ray sources in ECDF-S (Treister+, 2009)J/ApJS/191/124 : Opt. spectroscopy of ECDF-S X-ray sources (Silverman+, 2010)J/MNRAS/413/1206 : XMM survey of 12um selected galaxies (Brightman+, 2011)J/ApJ/728/58 : Swift-BAT survey of AGNs (Burlon+, 2011)J/A+A/530/A42 : X-ray properties of AGNs in XBS (Corral+, 2011)J/ApJ/740/37 : Obscured AGN at z~0.5-1 in the CDFS (Luo+, 2011)J/ApJ/742/61 : Phot. redshift of AGNs from XMM- & C-COSMOS (Salvato+ 2011)J/ApJS/195/10 : The CDF-S survey: 4Ms source catalogs (Xue+, 2011)J/ApJ/748/124 : AGN X-ray variability in the 4Ms catalog (Young+, 2012)J/ApJS/207/19 : Swift-BAT 2004-2010 hard X-ray survey (Baumgartner+, 2013)J/A+A/555/A42 : The XMM-CDFS catalogues (Ranalli+, 2013)J/MNRAS/443/1999 : X-ray spectral analysis of AGNs (Brightman+, 2014)J/ApJ/788/159 : 17 Seyfert 1 galaxies light curves (Koshida+, 2014)J/A+A/563/A57 : Long-term variability of AGN at hard X-rays (Soldi+, 2014)J/A+A/579/A115 : SUDARE-VOICE variability-selection of AGN (Falocco+, 2015)J/ApJ/802/89 : Luminosity function of X-ray-selected AGNs (Buchner+, 2015)J/ApJ/815/L13 : Compton-thick AGNs from Swift/BAT 70-months (Ricci+, 2015)J/A+A/588/A70 : Hard X-ray view of the soft excess in AGN (Boissay+, 2016)J/ApJS/224/15 : Improved 2Ms and 250ks Chandra catalogs (Xue+, 2016)J/ApJ/831/145 : 6Ms Chandra long-term analyses of AGNs (Yang+, 2016)J/MNRAS/471/364 : Spectral curvature values for AGNs (Baronchelli+, 2017)J/ApJS/228/2 : Chandra Deep Field-South survey: 7Ms sources (Luo+, 2017)J/ApJS/232/8 : AGNs X-ray spectral analyses from 7Ms CDF-S (Liu+, 2017)J/ApJS/236/48 : The Chandra UDS survey (X-UDS) (Kocevski+, 2018)J/ApJ/869/171 : Chandra observations of NuSTAR sources (Tomsick+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/877/5https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/877/5http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/877/5https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/877/5https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/877/5http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/877/5GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/877/5/table2 (X-ray spectral fitting results for highly obscured AGNs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/877/5/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/877/5/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/877/5/table2?GETtext/xml+votable180.050000true188.84107262.2502560.0055555555555555566/11230 11252 35935 35957https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/877/5?format=asciiX-raydefaultJ/ApJ/877/5/table2X-ray spectral fitting results for highly obscured AGNsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldCDF North or Southobs.fieldcharXID[4/1004] Identifier, 2Ms CDF-N catalog or 7Ms CDF-S catalog (1)meta.id;meta.mainintRAJ2000[52.91/189.71] Right ascension of X-ray source (J2000)degpos.eq.ra;meta.mainDEJ2000[-28/62.45] Declination of X-ray source (J2000)degpos.eq.dec;meta.mainzFINAL[0.18/5.4] Final redshift adopted (2)src.redshift;pos.heliocentricfloatf_zFINALRedshift type; "ZSPEC" (191 occurrences) or "ZPHOT"meta.codecharGamma[1.4/2.6] Photon indexmeta.code;spect.indexfloate_Gamma[1.4/2.4]? 1 sigma lower limit value of Gammastat.errorfloatnullableE_Gamma[1.4/2.6]? 1 sigma upper limit value of Gammastat.error;stat.maxfloatnullablef_GammaFlag of whether photon index is fixedmeta.codecharNH[0.1/8.6] Hydrogen column density1e+24cm**-2phys.columnDensityfloate_NH[0.01/6.3]? 1 sigma lower limit value of NH1e+24cm**-2stat.errorfloatnullableE_NH[0.1/8]? 1 sigma upper limit value of NH1e+24cm**-2stat.error;stat.maxfloatnullablelogL[42/45.3] log of 2-10keV absorption corrected luminosity (in erg/s)log(1e-07W)phys.luminosity;em.X-rayfloatCts[20/4191] 0.5-7keV net countsctphot.count;em.X-rayintHR[-0.6/0.93]? Hardness ratio (3)phot.flux;arith.ratiofloatnullableModelBest fit spectral fitting model (4)stat.fit;meta.modelledcharSimbadSimbad column added by the CDSmeta.ref.urlchar