J/ApJ/906/5ivo://CDS.VizieR/J/ApJ/906/5doi:10.26093/cds/vizier.19060005CDSAmaya-Almazan R.A.Chavushyan V.Patino-Alvarez V.M.2022-06-13T09:59:26Z2022-05-31T06:39:37ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiultraviolet-photometryOver the years, the flat-spectrum radio quasar 3C454.3 has presented phases of very high activity (flares) in which the different wave bands increase their flux dramatically. In this work, we perform multiwavelength analysis from radio to gamma-rays and study the MgII {lambda}2798 emission line and the UV FeII band from 2008 to 2018. We found that an increase in the 43GHz flux density of the quasi-stationary component C coincides with the estimated time at which a superluminal blob ejected from the radio core (which caused the brightest flare of 2010) collides with the quasi-stationary component (at a projected distance of ~4.6pc from the radio core). The different behavior of the spectral index in the first (5000<JD-2,450000<5600) and second (6600<JD-2450000<7900) flaring periods suggests changes in the physical conditions. The complex nature of the second period can be a result of a superposition of multiple events at different locations. The MGII line has an anticorrelation with the UV continuum while Fe ii correlates positively, except at the time of the brightest flare of 2010, when both have a strong response at high continuum luminosities. Our results suggest that the dominant gamma-ray emission mechanism for the first flaring period is external Compton. For the second flaring period the region emitting seed photons is co-spatial with that emitting gamma-rays. However, a study of the spectral energy distribution using a multizone jet emission model is required to confirm the nature of each significant flare during the second period.2021ApJ...906....5Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/906/5CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)J/ApJ/748/49 : Optical spectroscopy of 1LAC broad-line blazars (Shaw+, 2012)J/ApJ/763/L36 : MgII and FeII flux of the blazar 3C 454.3 (Leon-Tavares+, 2013)J/ApJ/846/98 : Jet kinematics of blazars at 43GHz with VLBA (Jorstad+, 2017)J/AJ/155/90 : 1996-2009 optical photometric monitoring for 3C66A (Fan+, 2018)J/A+A/630/A56 : A gamma-ray emission zone in 3C 279 (Patino-Alvarez+, 2019)J/ApJ/891/68 : MgII, FeII & 3000{AA} continuum LCs CTA102 (Chavushyan+, 2020)J/ApJS/248/8 : 9-yr of Fermi-LAT & Swift obs. of 3C 454.3 flares (Das+, 2020)J/ApJS/247/33 : The Fermi LAT fourth source catalog (4FGL) (Abdollahi+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/906/5https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/906/5http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/906/5https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/906/5https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/906/5http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/906/5GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVdefaultJ/ApJ/906/5/table1Flux measurements for the MgII {lambda}2798{AA} emission line, the FeII UV band, and the {lambda}3000{AA} continuumrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[5086/8307] Julian Date of observation, JD-2450000dtime.epochfloatCont[0.04/0.97] Continuum (3000{AA}) flux, 10^-13^erg/s/cm^2^/{AA}^phot.flux;em.UVfloate_Cont[0.001/0.03] Uncertainty in Contstat.errorfloatMgII[0.76/1.8] MgII 2798 flux, 10^-13^erg/s/cm^2^1e-13mW.m**-2phot.flux;em.UVfloate_MgII[0.03/0.85] Uncertainty in MgII1e-13mW.m**-2stat.errorfloatFeII[0.28/1.63] UV FeII flux, 10^-13^erg/s/cm1e-13mW.m**-2phot.flux;em.UVfloate_FeII[0.04/1.04] Uncertainty in FeII1e-13mW.m**-2stat.errorfloat