J/A+A/700/A203ivo://CDS.VizieR/J/A+A/700/A203doi:10.26093/cds/vizier/bc-nw/lcadCDSTrefoloni B.Ji X.Maiolino R.D'Eugenio F.Uebler H.Scholtz J.,Marconi A.Marconcini C.Mazzolari G.2026-08-03T06:56:26Z2025-08-25T08:36:07ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiquasarsspectroscopychemical-abundancesRecent JWST observations have revealed a large population of intermediate/low-luminosity active galactic nuclei (AGN) at early times with peculiar properties, different from local AGN or luminous quasars. To better understand the physical conditions in the broad-line regions (BLRs) of these early AGN, we used the optical FeII (4434-4684{AA}) and the broad Hbeta emission, and the ratio between their equivalent widths RFe, as a probe on a purposefully assembled sample. Specifically, we gathered a sample of 31 high redshift (<z>=6.5) AGN, observed by JWST, with broad Hbeta detection both in the high and low luminosity regimes (respectively 14 faint AGN and 17 quasars), to investigate their optical FeII emission properties. In addition, we carefully selected control samples at lower z. We found that the population of faint AGN (log(L_Hb_/(erg/s))<~44) exhibits a significantly lower FeII emission than their local counterparts having a mean (median) R_Fe_<0.24 (0.12) versus R_Fe_~=0.90 (0.79) in the control sample. At the same time, the quasars at the epoch of reionisation observed by JWST present a FeII emission profile that closely resembles that observed at z<3. We argue that the weakness of the FeII bump in the faint JWST AGN might be due to the reduced metallicity of their broad line region (<~0.5Z_{sun}_), while luminous quasars have already reached chemical maturity (~Z{_sun}_ or higher). Lastly, we highlight an intriguing similarity between the spectral properties of the high redshift population of faint AGN with those harboured in local metal poor dwarf galaxies.2025A&A...700A.203Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/700/A203CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/700/A203https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/700/A203http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/700/A203https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/700/A203https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/700/A203http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/700/A203GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/700/A203/tablea1 (The broad lines spectral properties estimated from the spectral fits of our sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/700/A203/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/700/A203/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/700/A203/tablea1?GETtext/xml+votable180.050000true53.07887-27.88420.0055555555555555566/848 2187 5630 11252 11425 16486 17770 17872 18242 22683 23078 26869 27124 27256 27258 27440 27467 27620 33762 35100 35518 35727 35895 35935 46954 47961 48715https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/700/A203?format=asciidefaultJ/A+A/700/A203/tablea1The broad lines spectral properties estimated from the spectral fits of our samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the sourcemeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainHbprofile[GL] Hbeta line profile, G=Gaussian, L=Lorentzianmeta.codecharlogLHbLogarithm of the Hbeta luminositylog(1e-07W)phys.luminosityfloate_logLHbUncertainty on the logarithm of the Hbeta luminositylog(1e-07W)stat.errorfloatRFeRatio of the optical FeII (4434-4684{AA}) and the broad Hbeta emission equivalent widthsspect.line.intensity;arith.ratiofloate_RFeUncertainty on the RFestat.errorfloatFWHMHbFWHM of the Hbeta linekm/sspect.line.widthinte_FWHMHbUncertainty on the FWHM of the Hbeta linekm/sstat.errorintSimbadNameSimbad column added by the CDSmeta.idcharnullablelogEWOIII? Logarithm of the equivalent width of [OIII]5007log(0.1nm)spect.line.eqWidthfloatnullablee_logEWOIII? Uncertainty on the logarithm of the equivalent width of [OIII]5007log(0.1nm)stat.errorfloatnullableO3Hb? Ratio between [OIII]5007 and narrow Hbetameta.notefloatnullablee_O3Hb? Uncertainty on the ratio between [OIII]5007 and narrow Hbetastat.errorfloatnullableO32? Ratio between [OIII]5007 and [OII]3728spect.line.intensity;arith.ratiofloatnullablee_O32? Uncertainty on the ratio between [OIII]5007 and [OII]3728stat.errorfloatnullableOabund? Oxygen abundance, 12+log(O/H)phys.abundfloatnullablee_Oabund? Uncertainty on the oxygen abundancestat.errorfloatnullableJ/A+A/700/A203/tableb1Luminosities, black hole mass and Eddington ratiorecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the sourcemeta.id;meta.maincharlogL5100Logarithm of the 5100{AA} luminositylog(1e-07W)phys.luminosity;em.optfloate_logL5100Uncertainty on the logarithm of the 5100{AA} luminositylog(1e-07W)stat.errorfloatlogLbolLogarithm of the bolometric luminositylog(1e-07W)phys.luminosityfloate_logLbolUncertainty on the logarithm of the bolometric luminositylog(1e-07W)stat.errorfloatlogMBHLogarithm of the black hole masssolMassphys.massfloate_logMBHUncertainty on the logarithm of the black hole masssolMassstat.errorfloatlogErLogarithm of the Eddington ratiophys.luminosity;arith.ratiofloate_logErUncertainty on the logarithm of the Eddington ratiostat.errorfloat