J/ApJ/936/39ivo://CDS.VizieR/J/ApJ/936/39doi:10.26093/cds/vizier.19360039CDSSicilian D.Civano F.Cappelluti N.Buchner J.Peca A.2026-02-10T20:05:31Z2024-08-23T12:05:14ZCDS support team

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

cds-question@unistra.frx-ray-sourcesactive-galactic-nucleiredshiftedWe have computed obscured active galactic nuclei (AGN) redshifts using the XZ method, adopting a broad treatment in which we employed a wide-ranging data set and worked primarily at the XZ counts sensitivity threshold, culminating with a redshift catalog containing 121 sources that lack documented redshifts. We considered 363 obscured AGN from the Chandra Source Catalog Release 2.0, 59 of which were selected using multiwavelength criteria while 304 were X-ray selected. One third of the data set had crossmatched spectroscopic or photometric redshifts. These sources, dominated by low-z and low-NH AGN, were supplemented by 1000 simulations to form a data set for testing the XZ method. We used a multilayer perceptron neural network to examine and predict cases in which XZ fails to reproduce the known redshift, yielding a classifier that can identify and discard poor redshift estimates. This classifier demonstrated a statistically significant ~3{sigma} improvement over the existing XZ redshift information gain filter. We applied the machine-learning model to sources with no documented redshifts, resulting in the 121 source new redshift catalog, all of which were X-ray selected. Our neural network's performance suggests that nearly 90% of these redshift estimates are consistent with hypothetical spectroscopic or photometric measurements, strengthening the notion that redshifts can be reliably estimated using only X-rays, which is valuable to current and future missions such as Athena. We have also identified a possible Compton-thick candidate that warrants further investigation.2022ApJ...936...39Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/936/39CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/simbad : Simbad objects catalogue (M.Wenger 2000)II/281 : 2MASS 6X Point Source Working Database / Catalog (Cutri+ 2006)IX/45 : The Chandra Source Catalog, Release 1.1 (Evans+ 2012)I/345 : Gaia DR2 (Gaia Collaboration, 2018)IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)J/A+A/393/425 : Spectral analysis of Lockman Hole (Mainieri+, 2002)J/A+A/467/73 : 3{sigma} hard sample of XMDS survey (Tajer+, 2007)J/MNRAS/413/1206 : XMM survey of 12um selected galaxies (Brightman+, 2011)J/ApJS/201/30 : The Chandra COSMOS survey. III. (Civano+, 2012)J/A+A/564/A125 : AGN Torus model comparison of AGN in CDFS (Buchner+, 2014)J/ApJ/802/89 : Luminosity function of X-ray-selected AGNs (Buchner+, 2015)J/ApJ/817/34 : C-COSMOS Legacy sources multiwavelength (Marchesi+, 2016)J/MNRAS/473/4937 : AllWISE ctp to ROSAT/2RXS & XMMSLEW2 cat. (Salvato+, 2018)J/A+A/618/A66 : Redshifts of obscured AGN (Simmonds+, 2018)J/MNRAS/505/1954 : Properties and X-rays of RLQs and RQQs quasars (Zhu+, 2021)J/A+A/661/A5 : The eFEDS AGN catalog (Liu+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/936/39https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/936/39http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/936/39https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/936/39https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/936/39http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/936/39GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/936/39/table10 (X-Ray redshift catalog for the 121 sources in our fully filtered no-z data set)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/936/39/table10?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/936/39/table10?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/936/39/table10?GETtext/xml+votable180.050000true1.8985819.535040.0055555555555555566/597 929 1539 2155 2436 2441 5999 7606 8072 8225 8921 10484 10761 10905 11027 11434 16197 16437 16655 16703 16952 17492 18962 19881 21438-21439 21456 21458 22855 22873 27773 33094 33295 33321 33657 34533 36048 40432 42666 42981 43233 43262 43881 44820 45446 45867 46005 46494 47828https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/936/39?format=asciiX-raydefaultJ/ApJ/936/39/table10X-Ray redshift catalog for the 121 sources in our fully filtered no-z data setrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource identifiermeta.id;meta.maincharRAJ2000[1/347] Degree of right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-74/76] Degree of declination (J2000)degpos.eq.dec;meta.mainNspec[1/11] Number of available spectrameta.numberintCts[162/92424] Number of Chandra broadband spectral countsphot.count;em.X-rayintHR[-0/1] X-ray Hardness Ratio ((H-S)/(H+S); soft:0.5-2keV and hard:2-7keV)phot.flux;arith.ratiofloatlogLX[42.45/47.06] log of rest-frame 2-10keV luminosityphys.luminosity;em.X-rayfloate_logLX[0.1/3.3] Negative error on logLXstat.errorfloatE_logLX[0.09/3] Positive error on logLXstat.error;stat.maxfloatGamma[1.54/2.8] Power-law photon index ({Gamma})spect.indexfloate_Gamma[0/0.3] Negative error on Gammastat.errorfloatE_Gamma[0/0.2] Positive error on Gammastat.error;stat.maxfloatlogNH[22.06/24.01] XZ modelled log N_H_phys.columnDensityfloate_logNH[0.01/0.7] Negative error on logNHstat.errorfloatE_logNH[0.01/0.4] Positive error on logNHstat.error;stat.maxfloatz[0.014/5] XZ modelled redshiftsrc.redshiftfloate_z[0.003/1.3] Negative error on zstat.error;src.redshiftfloatE_z[0.001/1.5] Positive error on zstat.error;stat.maxfloatP[0.53/1] MLP-computed probability that the redshift estimate is successful (P_+_)stat.probabilityfloatSimbadSimbad column added by the CDSmeta.ref.urlchar