J/ApJ/880/32ivo://CDS.VizieR/J/ApJ/880/32doi:10.26093/cds/vizier.18800032CDSLiodakis I.Romani R.W.Filippenko A.V.Kocevski D.Zheng W.2021-07-05T06:52:58Z2021-01-26T09:52:40ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsquasarsactive-galactic-nucleiredshiftedvisible-astronomygamma-ray-astronomyEven with several thousand Fermi-Large Area Telescope (LAT) blazar detections, the {gamma}-ray emission mechanism is poorly understood. We explore correlated optical/{gamma}-ray flux variations for 178 Fermi-LAT blazars regularly monitored by the Katzman Automatic Imaging Telescope, the Small and Moderate Aperture Research Telescope System, and the Steward Observatory. Out of the 178 sources, 121 show a measurable (>1{sigma}) discrete correlation function peak. Using the derived time lags and Bayesian block light-curve decompositions, we measure the fraction of common and orphan flares between the two bands. After accounting for sampling and sensitivity limitations we quantify for the first time the true orphan flare rates of optical and {gamma}-ray flares: 54.5% of optical and 20% of {gamma}-ray flares are orphan events. Both the intraband temporal relation and the small orphan {gamma}-ray flare fraction point toward leptonic processes as the likely mechanisms for the high-energy emission. Motivated to discriminate between synchrotron self-Compton (SSC) and external-Compton dominance in individual sources, we use the flux-flux variations to determine the slope m of the log fopt-log f{gamma} dependence. The slope distribution suggests a bimodal population with high and intermediate synchrotron peak objects showing larger m than low synchrotron peak objects. We find that m is naturally decreased through pollution from the orphan (typically optical) flares and develop a method to statistically recover, given the sources' measured orphan flare rate, the intrinsic m. While source classes show composite behavior, the majority of BL Lac objects favor m=2, indicating an SSC origin for the {gamma}-rays. No preference for either m is found in flat spectrum radio quasars.2019ApJ...880...32Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/880/32CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/5 : UBV Photometry of Bright Stars (Johnson+ 1966)VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)J/A+A/445/441 : SED of BL Lacertae objects (Nieppola+, 2006)J/A+A/488/867 : Synchrotron peak frequency of 135 AGN (Nieppola+, 2008)J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010)J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)J/ApJ/813/51 : {gamma}-ray to IR study of CTA 102 (Casadio+, 2015)J/ApJ/810/L9 : 1.5Jy MOJAVE AGN sample and 3FGL data (Lister+, 2015)J/other/AstBu/70.264 : Sample of 877 blazars (Mingaliev+, 2015)J/MNRAS/467/4565 : Bimodal radio variability in OVRO blazars (Liodakis+, 2017)J/ApJ/866/137 : Bright blazars variability brightness temp. (Liodakis+, 2018)http://herculesii.astro.berkeley.edu/kait/agn/ : KAIT Fermi AGN monitoringhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/880/32https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/880/32http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/880/32https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/880/32https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/880/32http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/880/32GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/880/32/table1 (The discrete correlation function (DCF) and flux-flux correlation results for the sources in our sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/880/32/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/880/32/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/880/32/table1?GETtext/xml+votable180.050000true4.3992425-5.21160080.0055555555555555566/100 514 579 911 1085 2094 2295 2414 3023 3024 3431 4695 4770 4820 4964 5284 5423 5462 5817 5918 6018 6067 6088 6507 6647 6822 6888 7004 7038 7045 7346 7426 7548 7758 7896 8067 8199 8321 8466 8915 8972 9196 9460 9612 9633 9676 9723 10183 10280 10422 10605 10800 10843 11153 11212 11444 11522 11639 11649 12599 12604 12619 13179 13410 13640 13673 13705 13711 13820 13927 14797 15211 15286 15917 15969 16027 16298 16796 17184 17186 17364 17414 17516 17579 18253 18457 18624 18661 19370 19398 19756 19831 19907 20099 20141 20777 21121 21574 21768 21793 21935 21972 22363 22396 22501 22950 23015 23121 23127 23215 23691 23835 24027 24084 24260 24608 24828 24845 24902 25302 25630 25677 25864 25910 26131 26292 26303 26483 26695 26798 26983 27060 27310 28083 28352 28479 28492 28498 28517 29017 29570 29729 30036 30842 31407 31430 31663 31664 31894 32261 32311 32621 32712 34013 34085 34123 34572 35079 36058 36554 37385 40265 40479 40689 40762 40766 42901 43366 44908 45178 46055 46369 46964 47014 47540 48798 49037https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/880/32?format=asciiGamma-rayOpticaldefaultJ/ApJ/880/32/table1The discrete correlation function (DCF) and flux-flux correlation results for the sources in our sampleNameName (1)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClassClass (2)meta.code.classcharSEDSpectral energy distribution class (3)src.spType;instr.bandwidthcharz[0.0/2.2]? Redshiftsrc.redshiftfloatnullabletau[-106/86.3]? Derived time lagdtime.intervalfloatnullablee_tau[0.26/19.7]? Uncertainty in taudstat.errorfloatnullablel_DCFLimit flag on DCFmeta.code.errorcharDCF[1.0/3.5]? DCF peak significancestat.fit.goodness;stat.maxfloatnullablem[-0.22/3.12]? Slope of the optical-gamma ray log-log correlationstat.fit.paramfloatnullablee_m[0.02/1.6]? Uncertainty in mstat.errorfloatnullablerho[-0.14/0.9]? Spearman's test correlation coefficientstat.correlationfloatnullablep[0/0.97]? Probability associated with the Spearman testmeta.id.assoc;stat.probabilitydoublenullablef_p[i] i: probabilities <1E-56 have been set to zero by CDSmeta.codecharp1[0/0.98]? Probability of association with m=1, intrinsic linear slopestat.fit.goodnessdoublenullablep2[0/0.99]? Probability of association with m=2, intrinsic quadratic slopestat.fit.goodnessdoublenullableLC[lc] LC: KAIT light curve available; column added by CDSmeta.ref.urlcharSimbadNameSimbad column added by the CDSmeta.idchar_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