J/ApJ/831/145ivo://CDS.VizieR/J/ApJ/831/145doi:10.26093/cds/vizier.18310145CDSYang G.Brandt W.N.Luo B.Xue Y.Q.Bauer F.E.Sun M.Y.Kim S.,Schulze S.Zheng X.C.Paolillo M.Shemmer O.Liu T.Schneider D.P.,Vignali C.Vito F.Wang J.-X.2018-01-05T08:56:51Z2017-03-08T06:46:42ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleix-ray-sourcessurveysredshiftedWe perform long-term (~15 years, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6Ms Chandra Deep Field-South survey; the majority are in the redshift range of 0.6-3.1, providing access to penetrating rest-frame X-rays up to ~10-30keV. Of the 68 sources, 24 are optical spectral type I AGNs, and the rest (44) are type II AGNs. The timescales probed in this work are among the longest for X-ray variability studies of distant AGNs. Photometric analyses reveal widespread photon flux variability: 90% of AGNs are variable above a 95% confidence level, including many X-ray obscured AGNs and several optically classified type II quasars. We characterize the intrinsic X-ray luminosity (L_X_) and absorption (N_H_) variability via spectral fitting. Most (74%) sources show L_X_ variability; the variability amplitudes are generally smaller for quasars. A Compton-thick candidate AGN shows variability of its high-energy X-ray flux, indicating the size of reflecting material to be <~0.3pc. L_X_ variability is also detected in a broad absorption line quasar. The N_H_ variability amplitude for our sample appears to rise as time separation increases. About 16% of sources show N_H_ variability. One source transitions from an X-ray unobscured to obscured state, while its optical classification remains type I; this behavior indicates the X-ray eclipsing material is not large enough to obscure the whole broad-line region.2016ApJ...831..145Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/831/145CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)J/ApJS/224/15 : Improved 2Ms and 250ks Chandra catalogs (Xue+, 2016)J/ApJ/825/7 : Evolution of ~6Ms CDF-S galaxies (Lehmer+, 2016)J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)J/ApJ/808/184 : NuSTAR surveys: ECDF-S catalog (Mullaney+, 2015)J/A+A/579/A115 : SUDARE-VOICE variability-selection of AGN (Falocco+, 2015)J/A+A/564/A125 : AGN Torus model comparison of AGN in CDFS (Buchner+, 2014)J/A+A/563/A57 : Long-term variability of AGN at hard X-rays (Soldi+, 2014)J/MNRAS/436/3759 : ECDFS sources optical/IR counterparts (Bonzini+, 2013)J/A+A/555/A42 : The XMM-CDFS catalogues (Ranalli+, 2013)J/MNRAS/426/3334 : Australia Telescope Large Area Survey (Mao+, 2012)J/ApJ/748/124 : AGN X-ray variability in the 4Ms catalog (Young+, 2012)J/ApJ/746/54 : Chandra X-ray observations of SDSS-DR5 QSOs (Gibson+, 2012)J/A+A/542/A83 : CAIXA. II. AGNs from excess variance analysis (Ponti+, 2012)J/A+A/536/A84 : X-ray variability of AGN (Vagnetti+, 2011)J/ApJS/195/10 : The CDF-S survey: 4Ms source catalogs (Xue+, 2011)J/ApJ/726/20 : X-ray emission from quasars (Miller+, 2011)J/ApJS/191/124 : Optical spectrosc. of ECDF-S X-ray sources (Silverman+, 2010)J/ApJS/187/560 : Photometric redshifts of the 2Ms CDF-S (Luo+, 2010)J/ApJS/187/251 : Ultradeep Ks imaging in the GOODS-N (Wang+, 2010)J/ApJ/722/520 : Gamma-ray light curves of Fermi blazars (Abdo+, 2010)J/ApJ/698/740 : VLA survey of CDF-S. III. (Tozzi+, 2009)J/ApJ/693/1713 : Spectroscopy of X-ray sources in ECDF-S (Treister+, 2009)J/ApJ/692/758 : BAL QSOs in SDSS-DR5 (Gibson+, 2009)J/A+A/497/81 : Variability-selected AGN in CDFS (Boutsia+, 2009)J/ApJ/685/773 : X-ray-UV relations in SDSS DR5 QSOs (Gibson+, 2008)J/A+A/487/475 : X-ray variability of AGNs in Lockman Hole (Papadakis+, 2008)J/ApJ/657/116 : X-ray and UV parameters of radio-quiet quasars (Kelly+, 2007)J/A+A/465/1099 : Redshift catalog of 691 objects in CDFS (Ravikumar+, 2007)J/A+A/451/457 : X-ray properties of AGN in CDFS (Tozzi+, 2006)J/A+A/437/883 : K20 survey: spectroscopic catalogue (Mignoli+, 2005)J/ApJS/155/271 : CDF-South: Optical spectroscopy (Szokoly+, 2004)J/MNRAS/328/150 : KX redshift survey (Croom+, 2001)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/831/145https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/831/145http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/831/145https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/831/145https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/831/145http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/831/145GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/831/145/table3 (Source properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/831/145/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/831/145/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/831/145/table3?GETtext/xml+votable180.050000true52.9921-27.809430.0055555555555555566/35935https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/831/145?format=asciiX-rayOpticaldefaultJ/ApJ/831/145/table3Source propertiesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStandard Chandra CDF-S source identifiermeta.id;meta.maincharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainz[0.1/3.8] Adopted redshift (1)src.redshiftfloate_z[0.01/0.3]? The 1{sigma} error in z (2)stat.error;src.redshiftfloatnullableOTypeOptical spectral type (3)src.classcharOff[1.9/8] Off-axis anglearcmininstr.offsetfloatCts[648/11284] Full band, 0.5-7keV, total net counts; not aperture correctedctphot.count;em.X-rayfloatpPF[0/86] Photon-flux variability p-value%stat.fit.goodness;src.varfloatpHR[0/100] Hardness-ratio variability p-value%stat.fit.goodness;src.varfloatEpeg[0.5/2.7] Lower end of normalization band (4)keVem.energyfloatGood[0/44] Goodness of the spectral fitting (5)%stat.fit.goodnessfloatGamma[1/3] Power-law photon indexmeta.code;spect.indexfloatLxEpoch-mean, intrinsic luminosity, rest-frame 2-10keV; erg/s1e-07Wphys.luminosity;em.X-raydoubleNHEpoch-mean, Hydrogen column densitycm**-2phys.columnDensitydoubleDelAICL[-6/1060] Metric of Lx variability significance (6)stat.fit.goodnessfloatDelAICN[-6/84] Metric of NH variability significance (6)stat.fit.goodnessfloatsigma2L[-0.02/0.5] Normalized excess variance of LX variability (6)stat.variancefloate_sigma2L[0.001/0.3] Uncertainty in sigma2Lstat.errorfloatsigma2N[-0.05/0.2]? Normalized excess variance of NH variability (7)stat.variancefloatnullablee_sigma2N[0.001/0.2]? Uncertainty in sigma2Nstat.errorfloatnullableCCatData within 1" from Treister+, 2009, J/ApJ/693/1713; Tozzi+, 2009, J/ApJ/698/740; Szokoly+, 2004, J/ApJS/155/271; Silverman+, 2010, J/ApJS/191/124; Mignoli+, 2005, J/A+A/437/883; Ravikumar+, 2007, J/A+A/465/1099 and Mao+, 2012, J/MNRAS/426/3334meta.ref.urlintnullableNEDSimbad column added by the CDSmeta.ref.urlchar