J/ApJ/900/141ivo://CDS.VizieR/J/ApJ/900/141doi:10.26093/cds/vizier.19000141CDSPu X.Luo B.Brandt W.N.Timlin J.D.Liu H.Ni Q.Wu J.2022-05-18T12:46:57Z2022-02-02T12:33:19ZCDS support team

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

cds-question@unistra.frquasarsx-ray-sourcesredshiftedsurveysactive-galactic-nucleiWe investigate systematically the X-ray emission from type 1 quasars using a sample of 1825 Sloan Digital Sky Survey non-broad absorption line (non-BAL) quasars with Chandra archival observations. A significant correlation is found between the X-ray-to-optical power-law slope parameter ({alpha}_OX_) and the 2500{AA} monochromatic luminosity (L_2500{AA}_), and the X-ray weakness of a quasar is assessed via the deviation of its {alpha}_OX_ value from that expected from this relation. We demonstrate the existence of a population of non-BAL X-ray-weak quasars, and the fractions of quasars that are X-ray weak by factors of >=6 and >=10 are 5.8%+/-0.7% and 2.7%+/-0.5%, respectively. We classify X-ray-weak quasars (X-ray weak by factors of >=6) into three categories based on their optical spectral features: weak emission-line quasars (WLQs; CIV rest-frame equivalent width <16{AA}), red quasars ({Delta}(g-i)>0.2), and unclassified X-ray-weak quasars. The X-ray-weak fraction of 35_-9_^+12^% within the WLQ population is significantly higher than that within non-WLQs, confirming previous findings that WLQs represent one population of X-ray-weak quasars. The X-ray-weak fraction of 13_-3_^+5^% within the red quasar population is also considerably higher than that within the normal quasar population. The unclassified X-ray-weak quasars do not have unusual optical spectral features, and their X-ray weakness may be mainly related to quasar X-ray variability.2020ApJ...900..141Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/900/141CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)J/ApJS/92/53 : Einstein database of quasars. I. (Wilkes+, 1994)J/AJ/121/2308 : Sloan Digital Sky Survey quasar photometry (Richards+, 2001)J/AJ/130/387 : SDSS-ROSAT AGN data (Strateva+, 2005)J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)J/ApJS/165/1 : BAL QSOs from SDSS DR3 (Trump+, 2006)J/ApJ/685/773 : X-ray-UV relations in SDSS DR5 QSOs (Gibson+, 2008)J/ApJ/692/758 : BAL QSOs in SDSS-DR5 (Gibson+, 2009)J/ApJ/696/580 : Properties of weak emission-line QSOs (WLQ) (Shemmer+, 2009)J/ApJ/696/924 : UV and X-Ray radio-quiet QSOs (Gibson+, 2009)J/ApJ/699/782 : High-redshift SDSS-DR5 QSOs (Diamond-Stanic+, 2009)J/ApJ/699/800 : Mass functions of active black holes (Vestergaard+, 2009)J/A+A/493/339 : XMM-Newton serendipitous Survey. V. (Watson+, 2009)J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)J/A+A/512/A34 : XMM-COSMOS Type 1 AGNs (Lusso+, 2010)J/AJ/139/390 : BL Lac objects from SDSS-DR7 (Plotkin+, 2010)J/ApJ/726/20 : X-ray emission from quasars (Miller+, 2011)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)J/ApJS/195/10 : The CDF-S survey: 4Ms source catalogs (Xue+, 2011)J/ApJ/746/54 : Chandra X-ray observations of SDSS-DR5 QSOs (Gibson+, 2012)J/A+A/548/A66 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)J/ApJ/747/10 : X-ray and multiwavelength properties of 11 WLQs (Wu+, 2012)J/AJ/149/203 : Reddening of ~35000 quasars from SDSS (Krawczyk+, 2015)J/ApJ/805/122 : X-ray properties of PHL1811 analogs and WLQs (Luo+, 2015)J/ApJ/819/154 : SDSS-DR7 QSOs with X-ray and UV luminosities (Lusso+, 2016)J/ApJ/831/145 : 6Ms Chandra long-term analyses of AGNs (Yang+, 2016)J/ApJS/228/2 : Chandra Deep Field-South survey: 7Ms sources (Luo+, 2017)J/MNRAS/469/3163 : Properties of BAL quasars (McGraw+, 2017)J/A+A/616/A114 : CIV BAL disappearance in SDSS QSOs (De Cicco+, 2018)J/A+A/619/A95 : X-ray/UV ratio of AGN (Chiaraluce+, 2018)J/ApJ/862/22 : CIV broad abs. line SDSS QSO with Gemini (Rogerson+, 2018)J/MNRAS/492/719 : Chandra obs. of 2106 radio-quiet QSOs (Timlin+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/900/141https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/900/141http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/900/141https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/900/141https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/900/141http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/900/141GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/900/141/xqsos (Chandra observations and X-ray and optical properties (Tables 2 and 3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/900/141/xqsos?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/900/141/xqsos?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/900/141/xqsos?GETtext/xml+votable180.050000true0.06451640.87968560.0055555555555555565/2286-2287 2628 6814 6935 6940-6941 6979 6/0 687 689 691 700 747 1700 2060 2297 4103-4104 4109 4121 4124 4131 4139 4150 4178 4181-4182 4207 4215-4216 4229 4255 4279 4285 4350 4352 4367 4376 4402 4404 4407 4410 4447-4448 4512 4574 4577 4604 4613 4615 4640 4642 4672 4686 4689 4708 4718-4720 4730 4748 4759 4775 4780 4795 4801 4804 4808 4835 4838 4855 4940 4943 4954-4955 4990 5002 5005 5016 5018 5024 5027 5046 5048 5051 5059 5061 5069 5075 5080 5085-5086 5090 5094 5106 5116 5124 5126 5130 5151 5164 5170-5171 5209 5229 5299 5305 5311 5327 5345 5349 5351 5359 5362 5367 5370 5396 5413 5432 5437 5454 5457 5470 5483 5486 5504 5518-5519 5523-5524 5536-5538 5569 5572 5591 5617 5625 5628 5648 5660 5668-5669 5675-5677 5687 5694 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9314 9328 9336 9342-9343 9354 9359 9365 9367 9371 9375 9387 9401 9429 9434 9443 9464 9466 9468 9472 9476 9504 9506 9508 9512 9612-9613 9618 9632-9633 9638 9650 9732 9742 9747 9769 9776 9785 9796 9800 9809 9811-9812 9825 9828 9837 9855 9878-9879 9986 9989 9992 9994 9997 10016 10074 10104 10122 10144 10153 10213 10220 10245 10302 10306-10307 10312-10313 10315 10318 10345 10358 10364 10367 10371 10374 10391 10394 10404 10413 10464-10465 10471 10475 10478 10484-10485 10501 10516-10518 10520 10527 10529-10530 10560 10574 10582 10589 10601 10607 10613 10618 10637 10640 10650 10664 10688 10690 10694 10704 10734 10749 10761 10765 10771 10777 10780-10781 10783 10788-10789 10816-10817 10822 10841 10843 10883-10884 10888 10894 10900 10905-10906 10911 10968 10970 11027 11061 11073 11080 11176 11179 11191 11194 11204 11206 11249 11252-11253 11259 11262 11264 11287 11332 11342 11365 11368 11370 11372 11410 11424 11428 11455 11467 11791 11807 11832 11924 11940 12406 12653 17306-17307 17406-17407 17469 17497 17506 17559 17662 17672 17679 17683 17690 17692 17741 17745 17748 17752 17754-17755 17767 17772-17773 17782 17806 17809 17813 17815-17816 17819 17822 17825 17828-17829 17831 17840-17841 17849 17860 17978 17981 17987 17993 17997 18001 18003 18007 18009 18011 18014 18017 18019-18022 18024-18025 18032 18034 18054-18055 18060-18061 18063 18065 18071 18075-18077 18086 18088-18089 18091 18096-18098 18111-18112 18123-18124 18176 18184 18189 18207 18209 18212 18273 18324 18328 18335 18387 18391 18397-18398 18411 18421 18677 18683 18739 18741 18746 18772-18774 18780 18784 18789-18791 18794-18796 18800 18826 18837 18839 18852 18858 18880 18917 19026 19028 19033 19036 19041-19043 19046 19056 19058 19064 19087 19089 19091 19094 19097 19110 19216 19220 19327 19363 19432 19456-19457 19460 19468 19490 19493 19504 19506 19542 19546 19760 19842 19993 20130 20136 21872 21877 21885 21977 23053 23146 23182 23205 23207 23209 23214 25594-25595 25599 25844-25845 25852-25853 25906 25913 25919 25927 25934-25935 25938 25942 25945 25948 25950 25952 25956 25958 25964 25972 25977 25981 25983 25989 26002 26006 26014 26020 26022 26035 26037 26041 26046 26055-26056 26071 26073 26098 26100 26103 26115 26159 26166-26167 26169 26175 26181 26187 26189 26198 26203 26205 26209 26212 26215 26217 26233 26239 26260 26264 26271 26274 26276 26285 26292 26303 26310 26313-26314 26316-26318 26322 26324 26331 26336 26338 26340 26344 26361-26362 26365 26377 26417 26425 26427 26441 26452 26481 26493 26495 26513 26515 26539 26542 26547 26554 26561 26563 26594 26596 26600 26876 26951 26955 26957 26962 26966 26975 26979 26981 26985 26995-26996 27004-27005 27053 27060 27076 27080 27094-27095 27097 27105 27124 27126-27128 27133 27218 27221 27224 27227 27237 27239 27247 27269 27287 27305 27314 27318 27327 27341 27343 27361 27372 27382 27387 27391-27392 27420 27427-27428 27440-27441 27466-27467 27476-27477 27487 27511 27514-27515 27520 27530 27532 27537 27541 27571 27574 27580 27591 27595 27604 27609 27617 27643 27652 27661 27681 27694 27714-27715 27718-27719 27722-27725 27727 27730-27733 27735-27736 27738-27739 27756 27758 27768 27771-27774 27779 27810 27816 27832-27833 27846 27852-27853 27855 27861-27862 27865 27867 27872 27889 27906-27907 27913-27915 27928-27929 27931 27936-27937 27939 27942 27945 27947-27948 27954 27960 27962-27963 27970 27975-27976 28005 28015 28022 28032 28034 28037-28038 28045 28049 28054 28075 28080-28081 28118 28123 28127 28138 28141-28142 28154 28172-28173 28175 28181 28184 28188 28220-28221 28226 28237 28244 28249 28290 28300 28310 28328 28356 28374 28376 28389 28428-28430 28449 28488 28490 28495 28497 28504 28507 28511 28517 28529 28533 28538-28539 28542 28592 28608 28610 28612 28620 28631-28633 28648 31332 31359 31375 31404 31406 31422 31622 31625 31627 31725 32410 32432 32436 32484 32500 32503 32510 32685-32686 36773 36792-36794 36863 45044 49092 49094 49106https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/900/141?format=asciiX-raydefaultJ/ApJ/900/141/xqsosChandra observations and X-ray and optical properties (Tables 2 and 3)SamB[0/1] Member of sample B (5)meta.codeintl_CtsBBLimit flag on CtsBB (2)meta.code.errorcharNEDNED column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainSDSSSDSS designation (HHMMSS.ss+DDMMSS.s; J2000) (G1)meta.id;meta.maincharl_CtsSBLimit flag on CtsSB (2)meta.code.errorcharSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDR[7/10] SDSS Data releasemeta.id;meta.datasetintz[1.7/2.7] Redshift (1)src.redshiftfloatObsID[323/17627] Chandra observation identifiermeta.id;obs.param;obsintExp[0.6/166] Chandra effective exposure time in the broad bandkstime.duration;obs.exposurefloatCtsBB[1.9/841] Broad-band (0.5-7keV) net counts in source region (2)ctphot.count;em.X-rayfloate_CtsBB[1.3/39.5]? Lower uncertainty on CtsBBctstat.errorfloatnullableE_CtsBB[2.7/41]? Upper uncertainty on CtsBBctstat.error;stat.maxfloatnullableCtsSB[1.9/721] Soft-band (0.5-2keV) net counts in source region (2)ctphot.count;em.X-rayfloate_CtsSB[1.3/29.1]? Lower uncertainty on CtsSBctstat.errorfloatnullableE_CtsSB[2.7/30.1]? Upper uncertainty on CtsSBctstat.error;stat.maxfloatnullableCtsHB[1.9/212.8] Hard-band (2-7keV) net counts in source region (2)ctphot.count;em.X-rayfloate_CtsHB[1.3/22.4]? Lower uncertainty on CtsHBctstat.errorfloatnullableE_CtsHB[2.7/23.6]? Upper uncertainty on CtsHBctstat.error;stat.maxfloatnullableBRatio[0.04/10.25]? Band ratio, hard-band to soft-band counts (3)phot.flux;arith.ratiofloatnullablee_BRatio[0.02/9]? Lower uncertainty on BRatiostat.errorfloatnullableE_BRatio[0.03/84]? Upper uncertainty on BRatiostat.error;stat.maxfloatnullableGamma[-1.4/4] 0.5-7keV effective power-law photon index (4)meta.code;spect.index;em.X-ray.mediumfloate_Gamma[0.1/4.6]? Lower uncertainty on Gammastat.errorfloatnullableE_Gamma[0.1/2.3]? Upper uncertainty on Gammastat.error;stat.maxfloatnullableSamC[0/1] Member of sample C (5)meta.codeintiMag[-29.7/-22.8] Absolute i-band magnitudemagphys.magAbs;em.opt.IfloatF2keV[0.01/95] Rest-frame 2keV flux density, 10^-32^erg/cm^2^/s/Hz (6)1e-32mW.m**-2.Hz**-1phot.flux;em.X-rayfloatF0.5-7[0.1/54] Observed-frame 0.5-7keV flux, 10^-14^erg/cm^2^/s (7)1e-14mW.m**-2phot.flux;em.X-rayfloatlogLX[43.2/46] Logarithm of the rest-frame 2-10 keV luminosity, erg/s (7)1e-07Wphys.luminosity;em.X-rayfloatF2500[0.02/12.4] Rest-frame 2500{AA} flux density, 10^-27^erg/cm^2^/s/Hz1e-27mW.m**-2.Hz**-1phot.flux.densityfloataOX[-2.5/-0.9] Measured X-ray-to-optical power-law slope (6)spect.indexfloatDaOX[-1/0.43] Difference between the measured and expected aOX (8)stat.fit.residualfloatfweak[0.1/415] X-ray weakness factor measured from DaOXstat.fit.paramfloatREW[0.9/479.1] Rest-frame equivalent width, CIV1549{AA} emission line0.1nmspect.line.eqWidthfloatD(g-i)[-0.97/2.67] Relative g-i color indexmagphot.color;em.opt.B;em.opt.IfloatR[1.3/247.2] Radio-loudness parameter (9)phot.flux;arith.ratiofloatXWeak[0/1] X-ray weak flag (10)meta.codeintl_CtsHBLimit flag on CtsHB (2)meta.code.errorcharl_F2keVLimit flag for f2keVmeta.code.errorcharl_F0.5-7Limit flag for F0.5-7meta.code.errorcharl_logLXLimit flag for logLXmeta.code.errorcharl_aOXLimit flag for aOXmeta.code.errorcharl_DaOXLimit flag for DaOXmeta.code.errorcharl_fweakLimit flag for fweakmeta.code.errorcharl_RLimit flag on Rmeta.code.errorcharSloanDisplay the online SDSS-DR14 data for the nearest objectmeta.ref.urlchar