J/MNRAS/477/4749ivo://CDS.VizieR/J/MNRAS/477/4749doi:10.26093/cds/vizier.74774749CDSCostamante L.Cutini S.Tosti G.Antolini E.Tramacere A.2024-08-18T20:19:23Z2021-08-20T14:23:47ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiquasarsgamma-ray-astronomyThe gamma-ray emission in broad-line blazars is generally explained as inverse Compton (IC) radiation of relativistic electrons in the jet scattering optical-UV photons from the broad-line region (BLR), the so-called BLR external Compton (EC) scenario. We test this scenario on the Fermi gamma-ray spectra of 106 broad-line blazars detected with the highest significance or largest BLR, by looking for cut-off signatures at high energies compatible with {gamma}-{gamma} interactions with BLR photons. We do not find evidence for the expected BLR absorption. For 2/3 of the sources, we can exclude any significant absorption ({tau}_max_<1), while for the remaining 1/3 the possible absorption is constrained to be 1.5-2 orders of magnitude lower than expected. This result holds also dividing the spectra in high- and low-flux states, and for powerful blazars with large BLR. Only 1 object out of 10 seems compatible with substantial attenuation ({tau}_max_>5). We conclude that for 9 out of 10 objects, the jet does not interact with BLR photons. Gamma-rays seem either produced outside the BLR most of the time, or the BLR is ~100 x larger than given by reverberation mapping. This means that (i) EC on BLR photons is disfavoured as the main gamma-ray mechanism, versus IC on IR photons from the torus or synchrotron self-Compton; (ii) the Fermi gamma-ray spectrum is mostly intrinsic, determined by the interaction of the particle distribution with the seed-photon spectrum; and (iii) without suppression by the BLR, broad-line blazars can become copious emitters above 100GeV, as demonstrated by 3C 454.3. We expect the CTA sky to be much richer of broad-line blazars than previously thought.2018MNRAS.477.4749Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/477/4749CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/810/14 : Third catalog of LAT-detected AGNs (3LAC) (Ackermann+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/477/4749https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/477/4749http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/477/4749https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/477/4749https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/477/4749http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/477/4749GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapGamma-raydefaultJ/MNRAS/477/4749/table1FSRQ blazars studied in this paperrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameNamemeta.id;meta.maincharn_Name[b] Note on Name (1)meta.notechar3FGL3LAC name (3FGL JHHMM.m+DDMM)meta.idcharzRedshiftsrc.redshiftdoublesigmaSignificance of the detection in the 3LAC (from Ackermann et al., 2015, Cat. J/ApJ/810/14)stat.fit.goodnessfloatn_sigma[b] Note on sigma (1)meta.notecharLBLR? Luminosity of the BLR (in 10+44erg/s)1e+37Wphys.luminosityfloatnullablen_LBLR[a] Note on LBLR (1)meta.notecharRBLR? Associated radius of the BLRcmphys.size.radiusdoublenullabletaumaxBLR? Maximum optical depth, at the peak of the {gamma}-{gamma} cross-section, for a path-length l=RBLR/2phys.absorption.opticalDepth;stat.maxfloatnullableRefsReferences for the BLR or emission lines luminosities (2)meta.ref;pos.framecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/MNRAS/477/4749/tablea1Spectral parameters of the fits of the gamma-ray SED datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject namemeta.id;meta.maincharzRedshiftsrc.redshiftdoubleF0.2-10GeVIntegral flux over the 0.2-10GeV bandcm**-2.s**-1phot.fluxdoubleGammaUPhoton index of the best-fit model below 13GeV rest-frame (Unabsorbed band)spect.indexfloate_GammaUrms uncertainty on GammaUstat.errorfloatbetaUCurvature of the best-fit model below 13GeV rest-frame (Unabsorbed band)meta.crypticfloate_betaU? rms uncertainty on betaUstat.errorfloatnullablechi2Uchi^2^ of the best-fit model below 13GeV rest-frame (Unabsorbed band)stat.fit.chi2floatDOFUDOF of the best-fit model below 13GeV rest-frame (Unabsorbed band)stat.fit.dofintGammaFPhoton index of the log-parabolic fit with BLR absorption (logptau), over the full LAT band and with all parameters freespect.indexfloate_GammaFrms uncertainty on GammaFstat.errorfloatbetaFCurvature of the log-parabolic fit with BLR absorption (logptau), over the full LAT band and with all parameters freemeta.crypticfloate_betaFrms uncertainty on betaFstat.errorfloatchi2Fchi^2^ of the log-parabolic fit with BLR absorption (logptau), over the full LAT band and with all parameters freestat.fit.chi2;phys.absorption;meta.modelledfloatDOFFDOF of the log-parabolic fit with BLR absorption (logptau), over the full LAT band and with all parameters freestat.fit.dofintchi2(logp)chi^2^ of the following fits over the full band: pure log-parabola with no BLR absorption (logp)stat.fit.chi2floatDOF(logp)DOF of the following fits over the full band: pure log-parabola with no BLR absorption (logp)stat.fit.dofintchi2(exp03)chi^2^ of the following fits over the full band: power-law with high-energy cutoff with beta=1/3 (exp03)stat.fit.chi2floatDOF(exp03)DOF of the following fits over the full band: power-law with high-energy cutoff with beta=1/3 (exp03)stat.fit.dofint