J/A+A/663/L7ivo://CDS.VizieR/J/A+A/663/L7doi:10.26093/cds/vizier.36639007CDSSacchi A.Risaliti G.Signorini M.Lusso E.Nardini E.Bargiacchi G.,Bisogni S.Civano F.Elvis M.Fabbiano G.Gilli R.Trefoloni B.,Vignali C.2022-09-30T22:42:41Z2022-07-22T08:57:31ZCDS support team

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

cds-question@unistra.frquasarsactive-galactic-nucleiredshiftedx-ray-sourcesultraviolet-astronomyvisible-astronomystellar-distanceThe non-linear relation between the X-ray and ultraviolet (UV) luminosity in quasars has been used to derive quasar distances and to build a Hubble diagram at redshifts up to z~7. This cosmological application is based on the assumption of independence of the relation on redshift and luminosity. We want to test the reliability of this hypothesis by studying the spectroscopic properties of high-redshift quasars in the X-ray and UV bands. We performed a one-by-one analysis of a sample of 130 quasars at z>2.5 with high-quality X-ray and UV spectroscopic observations. We found that not only the X-ray to UV correlation still holds at these redshifts, but its intrinsic dispersion is as low as 0.12dex (previous works reached 0.20-0.22 dex). For a sample of quasars at z~3 with particularly high-quality observations the dispersion further drops to 0.09dex, a value entirely accountable for by intrinsic variability and source geometry effects. The composite spectra of these quasars, in both the X-rays and the UV, do not show any difference with respect to the average spectra of quasars at lower redshifts. The absence of any spectral difference between high- and low-z quasars and the tightness of the X-ray to UV relation suggests that no evolutionary effects are present in the relation. Therefore, it can be safely employed to derive quasar distances. Under this assumption, we obtain a measurement of the luminosity distance at z~3 with 15% uncertainty, and in a 4 sigma tension with the concordance model.2022A&A...663L...7Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/663/L7CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/663/L7https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/663/L7http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/663/L7https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/663/L7https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/663/L7http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/663/L7GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/663/L7/sample (Properties of the final sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/663/L7/sample?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/663/L7/sample?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/663/L7/sample?GETtext/xml+votable180.050000true149.922581.97933270.0055555555555555565/6814 6/1700 2111 2188 2564 4104 4378 4557 4720 4723 4748 4946 4971 5112 5241 5272 5349 5367 5723 5952 5985 6069 6077 6472 8196 8707 9355 9506 9576 9801 9898 10312-10313 10378 10383 10911 10992 11080 11195 11308 11355 11433 11498 11596 11802 11854 11931 17266 17357 17679 17749 17980 18009 18018 18185 18200 18302 18858 19042 19315 19609 19676 20055 20060 20386 21873 23197 23210 25936 25972 25981 26005 26037 26052 26175 26189 26313 26417 26427 27124 27127 27245 27247 27314 27344 27365 27742 27889 27907 28029 28050 28147 28648https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/663/L7?format=asciiX-rayUVOpticaldefaultJ/A+A/663/L7/sampleProperties of the final samplezRedshiftsrc.redshiftdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameQuasar namemeta.id;meta.maincharRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainGxPhoton indexmeta.code;spect.indexdoublee_GxLower error on photon indexstat.errordoubleE_GxUpper error on photon indexstat.error;stat.maxdoublelogLUVRest-frame luminosities at 2500 Angstroem (1)log(1e-07W)phys.luminosity;em.UVdoublelogFUVRest-frame fluxes at 2500 Angstroem (2)log(mW.m**-2)phot.flux;em.UVdoublee_logLUVError on rest-frame luminosity at 2500 Angstroemlog(1e-07W)stat.errordoublelogLXRest-frame luminosities at 2keV (1)log(1e-07W)phys.luminosity;em.X-raydoublelogFXRest-frame fluxes at 2keV (2)log(mW.m**-2)phot.flux;em.X-raydoublee_logLXLower error on rest-frame luminosity at 2keVlog(1e-07W)stat.errordoubleE_logLXUpper error on rest-frame luminosity at 2keVlog(1e-07W)stat.error;stat.maxdoubleSimbadNameSimbad column added by the CDSmeta.idcharnullable