J/A+A/655/A109ivo://CDS.VizieR/J/A+A/655/A109doi:10.26093/cds/vizier.36550109CDSBisogni S.Lusso E.Civano F.Nardini E.Risaliti G.Elvis M.,Fabbiano G.2021-12-06T23:12:08Z2021-12-01T09:03:21ZCDS support team

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

cds-question@unistra.frquasarsactive-galactic-nucleiredshiftedx-ray-sourcesultraviolet-astronomyvisible-astronomysurveysspectroscopyphotometryWe present a study of the relation between X-rays and ultraviolet emission in quasars for a sample of broad-line, radio-quiet objects obtained from the cross-match of the Sloan Digital Sky Survey DR14 with the latest Chandra Source Catalog 2.0 (2332 quasars) and the Chandra COSMOS Legacy survey (273 quasars). The non-linear relation between the ultraviolet (at 2500{AA}, LUV) and the X-ray (at 2keV, LX) emission in quasars has been proved to be characterised by a smaller intrinsic dispersion than the observed one, as long as a homogeneous selection, aimed at preventing the inclusion of contaminants in the sample, is fulfilled. By leveraging on the low background of Chandra, we performed a complete spectral analysis of all the data available for the SDSS-CSC2.0 quasar sample (i.e. 3430 X-ray observations), with the main goal of reducing the uncertainties on the source properties (e.g. flux, spectral slope). We analysed whether any evolution of the LX-LUV relation exists by dividing the sample in narrow redshift intervals across the redshift range spanned by our sample, z~=0.5-4. We find that the slope of the relation does not evolve with redshift and it is consistent with the literature value of 0.6 over the explored redshift range, implying that the mechanism underlying the coupling of the accretion disc and hot corona is the same at the different cosmic epochs. We also find that the dispersion decreases when examining the highest redshifts, where only pointed observations are available. These results further confirm that quasars are 'standardisable candles', that is we can reliably measure cosmological distances at high redshifts where very few cosmological probes are available.2021A&A...655A.109Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/655/A109CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/286 : SDSS quasar catalog, fourteenth data release (Paris+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/655/A109https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/655/A109http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/655/A109https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/655/A109https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/655/A109http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/655/A109GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/655/A109/table2 (Properties of the 3430 X-ray observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/655/A109/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/655/A109/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/655/A109/table2?GETtext/xml+votable180.050000true0.26145192.58422810.0055555555555555565/1805 1810 2287 2628-2629 6814 6941 6/0 552 687 689 691 700 1700 2051 2057 2111 2117 2125 2186 2214 2220 2247 2253 2564 4097 4103-4105 4121 4139 4150-4151 4181-4182 4196 4206 4215-4216 4229 4253 4255 4285 4298 4350 4401 4406-4407 4410 4448 4548 4574 4577 4596 4615 4642 4649 4672 4686 4690 4715 4718 4720 4730 4758-4759 4775 4801 4804-4805 4808 4850 4865 4867 4924 4927 4940 4943 4946 4948 4952 4955 4962 4964-4966 5002 5016 5018 5046 5048 5051 5059 5061 5069 5075 5082 5085-5087 5089 5098-5100 5103 5106 5116 5124 5130 5142 5149 5164 5171 5174 5181-5182 5236 5241 5284 5299 5305-5306 5311 5327 5349 5351 5367 5370 5396 5413 5437-5439 5450 5454 5470 5483 5491 5504 5514 5518 5523 5528 5536 5538 5563 5585 5587 5591 5597 5609 5616-5618 5625 5628 5633-5634 5652 5660 5662 5675 5677-5678 5701 5715 5723 5731-5733 5735 5743 5751 5764 5781 5793-5795 5797 5799 5816 5819 5841-5843 5848 5865 5881 5894 5902 5905-5906 5922 5925 5927-5928 5930 5939 5942 5945 5948 5955-5956 5959 5967 5975 5980 5982 5985 5988-5989 5995-5996 5999 6001 6010 6014 6019 6033 6038-6040 6042 6045-6048 6069 6071 6073 6075 6077 6079 6081 6084-6086 6090 6098 6100 6111-6113 6115 6196 6220 6236 6243 6258 6261 6263 6337 6389 6391 6427 6441 6448 6452 6454 6464 6487 6490 6495 6499 6509 6515 6534 6539 6549 6551-6552 6559 6576 6585 6591 6609 6611 6618-6619 6623 6638-6639 6645-6646 6652 7168 7173 7178 7214 7224-7225 7227-7228 7237 7239 7248 7251 7257 7259-7261 7264 7266 7273 7278-7279 7281 7301 7303 7309-7312 7318 7320 7323 7326 7330 7337 7345 7371 7378-7379 7384 7399 7424-7426 7428 7432 7455-7456 7459 7464 7478 7485 7500 7508 7522 7552 8193 8195-8198 8203-8204 8227 8234 8264 8266 8268 8282 8288 8338-8339 8345 8373 8396 8526 8537 8555 8574 8603 8642 8644 8648 8659 8674-8675 8681 8707 8733 8740-8741 8809 8835 8895 8906 8909 8915 8922 8959 8963 8969 8972 9009 9044 9047 9052 9069 9077 9118 9135 9145-9147 9168 9181 9185 9190 9230 9264 9287 9290 9342-9343 9362-9363 9365 9367-9368 9403 9428-9429 9434 9443 9446 9466 9468 9472 9477 9486 9496 9506 9508 9512 9650 9742 9747 9801 9812 9821 9828 9831 9837 9842 9848 9852 9855 9938 9986 9988-9989 9992 9994 9997 9999 10061 10072 10104 10122 10131 10144 10153-10155 10158 10190 10192 10202 10213 10220 10222 10306 10312-10313 10344-10345 10348 10358 10364 10367 10371 10378-10379 10391 10394 10404 10411 10413 10432 10442 10454 10465 10471 10475 10484-10485 10524 10527 10529 10551 10570 10579 10600-10601 10607 10618 10637 10650 10658 10664 10689-10690 10704-10706 10721 10723 10731 10734 10743 10745 10761 10769 10775 10780 10796 10816 10822 10835 10841 10856 10877 10888 10898 10901 10911-10912 10936 10948 10959 10963 10968-10970 10979 10982 10992 11000-11002 11006 11029-11030 11040 11042 11044 11047-11048 11050 11061 11063 11073 11080 11099 11101 11117 11127 11137 11149 11176 11179-11180 11184 11191 11194-11195 11204 11206 11214 11217 11222 11249 11252-11253 11259 11264 11272 11274 11279 11299 11339 11342 11347 11364-11365 11368 11371-11372 11408 11410 11418 11424-11425 11427-11428 11430 11434 11448 11457 11461-11462 11467 11512 11589 11596 11791 11802 11806-11807 11809-11810 11828 11832 11854 11905 11908 11940 12406 12631 13312 13314 13345 13362 13384 13402 13574 17237 17263 17306-17307 17406 17487 17497 17510 17565 17618 17622-17623 17662 17672 17679 17683 17686 17688-17690 17692 17699 17702 17719 17741-17742 17745 17752 17754-17755 17766-17767 17769 17772-17774 17780 17788 17806 17809 17813 17815-17816 17819 17822 17825 17827 17829 17834 17840 17848-17850 17860 17895 17985 17991 18001 18003 18007 18009 18011 18016-18017 18021-18022 18024 18032 18034 18042 18054-18055 18060-18061 18065 18067 18071 18076-18077 18081 18086 18088-18090 18096 18099 18111-18114 18124 18154 18176 18184 18200 18209 18212 18324 18328 18335 18365 18385 18406 18411 18520 18741 18746 18757 18772 18779-18780 18787 18789-18791 18795-18796 18800 18826 18837 18839 18858 18895 18923 18935 19029 19033 19036 19045-19046 19050 19056 19087 19089 19094 19097 19101 19110 19216 19218 19220 19285 19327 19363 19412 19432 19451 19456-19458 19460-19462 19609 19664 19678 19697 19710-19711 19760 19842 19846 19857 19881 19897 19904-19905 19935 19941 19950 19954 19993 20021 20025 20031 20053 20071 20073 20095 20130 20168 20177 20179 20186 20191 20203 20237 20292 20302 20344 21873 23053 23060 23182-23183 23185 23195 23204 23207 23209 23213 23234 25594 25844 25852 25919 25934 25948 25950 25960 25964 25972 25977 25981 26002 26005 26019 26022 26035 26058 26071 26091 26097 26100 26102-26103 26175 26177 26187 26189 26196 26206 26208-26209 26213 26217 26254 26266 26271 26276-26277 26281 26292 26295 26298 26303 26308 26313 26316-26317 26323 26330 26338 26344 26377 26417 26427 26441 26499 26531 26554 26563 26594 26596 26876 26951 26955 26962 26972 26975 26977 26981 26985 26990 26995 27004 27060 27080 27095 27105 27126-27128 27213 27231 27237 27245 27247 27269 27305 27318 27343-27344 27365 27372 27387 27391-27392 27402 27412 27420 27428 27441 27466 27476 27487 27509 27511 27514-27515 27518 27530 27532 27537 27541 27552 27578 27580 27582 27591 27604 27617 27641 27652 27694 27714 27718-27719 27725 27730 27733 27735-27738 27741-27743 27760 27773 27810 27846 27848 27852 27859 27861-27862 27865 27872 27884 27887 27889 27907-27908 27913-27914 27929 27931 27936-27937 27939 27942 27944 27950-27951 27954 27962 28005 28022 28034 28037-28038 28041 28044-28045 28077 28126-28127 28138 28142 28147 28184 28220-28221 28226 28237 28249 28251 28279 28361 28370 28374 28376-28377 28414 28416 28430 28452 28483 28486 28488 28490 28497 28511 28516 28518 28535 28538-28539 28542 28548 28569-28570 28574 28581 28592 28611 28631-28633 28663 28666 30040 31310 31313 31419 31422 31453 31629 31725 31730 32500 36728 36766 36773 36785 36792-36793 36846-36847 36863 45044 49011 49014 49106https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/655/A109?format=asciiX-rayUVOpticaldefaultJ/A+A/655/A109/table2Properties of the 3430 X-ray observationsNameQuasar name in DR14, HHMMSS.ss+DDMMSS.smeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintzRedshiftsrc.redshiftdoubleObsIdChandra Observation Identifiermeta.id;obs.param;obsintthetaOff-axis angle of source in X-ray observationlog(arcmin)obs.param;obsdoubleExpTimeExposure time of X-ray obs.log(s)time.duration;obs.exposuredoubleDRflagNumber of SDSS Data Release, DR7, DR12 or DR14meta.codecharlogF2500ARest-frame fluxes at 2500 Angstroem (1)log(mW.m**-2.Hz**-1)phot.flux;em.UVdoublee_logF2500AError on rest-frame fluxes at 2500{AA}log(mW.m**-2.Hz**-1)stat.errorfloatlogF2keVRest-frame fluxes at 2keVlog(mW.m**-2.Hz**-1)phot.flux;em.X-raydoublee_logF2keVLower error on fluxes at 2keVlog(mW.m**-2.Hz**-1)stat.errorfloatE_logF2keVUpper error on fluxes at 2keVlog(mW.m**-2.Hz**-1)stat.error;stat.maxfloatGammaPhoton indexmeta.code;spect.indexdoublee_GammaLower error on photon indexstat.errordoubleE_GammaUpper error on photon indexstat.error;stat.maxdoublelogF2keVlim? Rest-frame 2keV flux limit per observationphot.flux;em.X-raydoublenullablen_logF2keVlim[I] I for -Infinitymeta.notecharCtsRaw counts in soft band (0.5-2keV)phot.count;em.X-raydoubleCthRaw counts in hard band (2-7keV)phot.count;em.X-raydoubleSNsSN in the soft band (0.5-2keV)stat.snrdoubleSNh? SN in hard band (2-7keV)stat.snrdoublenullableSimbadNameSimbad column added by the CDSmeta.idcharnullable_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.main