J/ApJS/268/54ivo://CDS.VizieR/J/ApJS/268/54doi:10.26093/cds/vizier.22680054CDSXu J.Hu S.Chen X.Jiang Y.Alexeeva S.2024-11-06T20:30:05Z2024-02-07T15:38:04ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsinfrared-photometryvisible-astronomybroad-band-photometryWe developed a multiregion radiation model for the evolution of flux and spectral index with time. In this model, each perturbation component in the jet produces an independent flare. The model can be used to study the decomposition of microvariability, the structural scale of the perturbed components, and the physical parameters of the acceleration processes. Based on the shock acceleration model for a relativistic jet, the influence of the acceleration parameters on multiband flare parameters is calculated. We present the results of multiband optical microvariability of the blazar BL Lacertae observed during 89 nights in the period from 2009 to 2021, and use them as a sample for model fitting. The results show that both the amplitude and duration of flares decomposed from the microvariability light curves conform to a log-normal distribution. The time delays between the optical bands follow a normal distribution and amount to several minutes, which corroborate with both predictions from the theoretical model and the calculation of the discrete correlation function. Using the spectral index evolution and the simultaneous fitting of the multiband variability curves, we obtain the acceleration and radiation parameters to constrain and distinguish the origins of different flares. Based on the flare decomposition, we can effectively reproduce the time-domain evolution trends of the optical variations and energy spectrum, and explain the various redder-when-brighter and bluer-when-brighter behaviors.2023ApJS..268...54Xhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/268/54CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/PAZh/30/243 : BV(RI)c-JHK phot. of BL Lac in 1999-2001 (Hagen-Thorn+, 2004)J/AZh/71/717 : Polarimetric Observations of BL Lac (Gagen-Torn+ 1994)J/A+AS/116/403 : VRI photometry of stars in 12 BL Lac objects (Fiorucci+, 1996)J/A+AS/132/83 : BVRI photometry of 7 BL Lac objects (Bai+ 1998)J/A+AS/136/455 : BVRI photometry of 3 BL Lac objects (Bai+, 1999)J/ApJ/522/846 : Optical monitoring of GeV loud blazars (Xie+, 1999)J/A+A/369/758 : VRI photometry of BL Lac (1997-1999) (Fan+, 2001)J/A+A/385/55 : Long-Term Polarization of BL Lac (Hagen-Thorn+ 2002)J/MNRAS/373/209 : BATC eim photometry of BL Lac (Hu+, 2006)J/A+A/450/39 : BVRI photometry of 8 red blazars (Gu+, 2006)J/AJ/134/799 : Multiwaveband polarimetry of 15 AGN (Jorstad+, 2007)J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)J/A+A/558/A92 : S5 0716+714 microvariability observation (Bhatta+, 2013)J/ApJ/787/151 : Fitted jet components in BL Lacertae (Cohen+, 2014)J/ApJ/816/53 : Multiwavelength obs. of BL Lac in 2012-2013 (Wehrle+, 2016)J/A+A/609/A68 : Full-Stokes polarimetry of 5 radio sources (Myserlis+, 2018)J/A+A/620/A185 : Long-term optical monitoring of TeV Blazars (Nilsson+, 2018)J/A+A/623/A175 : 2015 BL Lac VHE gamma-ray flare (MAGIC Collaboration, 2019)J/ApJ/884/92 : 7yrs of VRI obs. of S5 0716+714 and its flares (Xu+, 2019)J/A+A/649/A153 : BL Lac 86GHz images (Casadio+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/268/54https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/268/54http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/268/54https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/268/54https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/268/54http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/268/54GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJS/268/54/fig1Light curves of BL Lac from Weihai observatory of Shandong UniversityrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[2455128.9/2459206.0] Julian datedtime.epochdoubleindexedBandObservational band (B, V, R or I)meta.code;instr.filtercharmag[10.8/14.7] Apparent magnitude in Band after the galactic extinction correctionmagphot.magfloate_mag[0.0007/0.05] Uncertainty in magmagstat.error;phot.magfloatJ/ApJS/268/54/table2Flare parameters used to fit the datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[2455128.9/2459206.0] Julian Datedtime.epochdoubleID[1/7] Flare index identifiermeta.idintBandObservational band (V, R or I)meta.code;instr.filtercharCenter[-3.1/14.7] Central time of the flarehtime.epochfloatAmp[0.039/19.41] Flare amplitude in BandmJysrc.var.amplitudefloatdN[0.08/161.5] Enhanced electron number density1e-05s**-1.m**-3meta.number;phys.density;phys.electrondoubleWidth[0.25/5.72] Flare width/duration, {tau}_flare_htime.intervalfloatSize[2.88/65.54] Size of the radiation region, S_cell_ (Equation 3)AUphys.size.radiusfloat