J/ApJS/247/27ivo://CDS.VizieR/J/ApJS/247/27doi:10.26093/cds/vizier.22470027CDSKapanadze B.Gurchumelia A.Dorner D.Vercellone S.Romano P.,Hughes P.Aller M.Aller H.Kharshiladze O.2025-11-03T20:15:15Z2020-11-06T12:23:03ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleix-ray-sourcesultraviolet-astronomyvisible-astronomygamma-ray-astronomyWe present the results from the timing and spectral study of Mrk 421 based mainly on the Swift data in the X-ray energy range obtained during the time interval 2015 December-2018 April. The most extreme X-ray flaring activity on long-term, daily, and intraday timescales was observed during the 2 month period that started in 2017 December, when the 0.3-10keV flux exceeded a level of 5x10^-9^erg/cm^2^/s, recorded only twice previously. While the TeV- band and X-ray variabilities were mostly correlated, the source often varied in a complex manner in the MeV-GeV and radio-UV energy ranges, indicating that the multifrequency emission of Mrk 421 could not always be generated in a single zone. The longer-term flares at X-rays and {gamma}-rays showed a lognormal character, possibly indicating a variability imprint of the accretion disk onto the jet. A vast majority of the 0.3-10keV spectra were consistent with the log-parabolic model, showing relatively low spectral curvature and correlations between the different spectral parameters, predicted in the case of the first- and second-order Fermi processes. The position of the synchrotron spectral energy distribution peak showed an extreme variability on diverse timescales between the energies Ep<0.1 and >15keV, with 15% of the spectra peaking at the hard X-ray, and was related to the peak height as S^p^{propto}E_p_^{alpha}^ with {alpha}~0.6, which is expected for the transition from Kraichnan-type turbulence into the "hard sphere" one. The 0.3-300GeV spectra showed features of the hadronic contribution, jet-star interaction, and upscatter in the Klein-Nishina regime in different time intervals.2020ApJS..247...27Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/247/27CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/swift : Swift Master Catalog (HEASARC, 2004-)VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)J/ApJS/197/24 : Chandra large-scale extragalactic jets. I. (Massaro+, 2011)J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)J/A+A/578/A22 : Mrk421 in March 2010 (Aleksic+, 2015)J/A+A/576/A126 : The 2009 multiwavelength campaign on Mrk421 (Aleksic+, 2015)J/A+A/593/A91 : Mrk 421 multi-wavelength variability, 2007-2009 (Ahnen+, 2016)J/ApJ/831/102 : Swift and NuSTAR obs. of the BL Lac Mrk 421 (Kapanadze+, 2016)J/ApJ/848/103 : ~1.5yr Swift observations of Mrk 421 (Kapanadze+, 2017)J/ApJ/854/66 : Swift observations of Mrk 421. I. 2005-2008 (Kapanadze+, 2018)J/ApJ/858/68 : Mrk 421 Swift obs. in selected epochs. II. (Kapanadze+, 2018)J/ApJS/238/13 : Spectral and timing results of 1ES 1959+650 (Kapanadze+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/247/27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/247/27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/247/27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/247/27https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/247/27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/247/27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapGamma-rayX-rayUVOpticaldefaultJ/ApJS/247/27/table2Summary of the XRT and UVOT observations in the time interval 2015 December-2018 AprilrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintobsID[10474002/93249013] Swift observation identifiermeta.id;obs.param;obsintstUTC date of observation startstime.start;obsnullableUTEndUTC time of observation endtime.epochnullableUTOff[1]? Offset in days if UTEnd is on a different UT Datedtime.intervalintnullableMJDModified Julian Date, observation startdtime.epochdoubleExp[45/6021]? Exposure timestime.duration;obs.exposureintnullableXRT[7/163]? Observation-binned 0.3-10keV count ratect/sphot.count;em.X-rayfloatnullablee_XRT[0.08/1.5]? Uncertainty in XRTct/sstat.errorfloatnullableuvw1mag[11/12.6]? De-reddened Swift/UVOT uvw1 band magnitudemagphot.mag;em.UVfloatnullablee_uvw1mag[0.03/0.2]? Uncertainty in uvw1magmagstat.error;phot.magfloatnullableFuvw1[8.4/30]? De-reddened Swift/UVOT uvw1 band flux densitymJyphot.flux;em.UVfloatnullablee_Fuvw1[0.04/1.3]? Uncertainty in Fuvw1mJystat.errorfloatnullableuvm2mag[11.2/13.1]? De-reddened Swift/UVOT uvm2 band magnitudemagphot.mag;em.UVfloatnullablee_uvm2mag[0.03/0.2]? Uncertainty in uvm2magmagstat.error;phot.magfloatnullableFuvm2[4.4/23.3]? De-reddened Swift/UVOT uvm2 band flux densitymJyphot.flux;em.UVfloatnullablee_Fuvm2[0.09/0.5]? Uncertainty in Fuvm2mJystat.errorfloatnullableuvw2mag[11/12.5]? De-reddened Swift/UVOT uvw2 band magnitudemagphot.mag;em.UVfloatnullablee_uvw2mag[0.03/0.4]? Uncertainty in uvw2magmagstat.error;phot.magfloatnullableFuvw2[7.6/26.3]? De-reddened Swift/UVOT uvw2 band flux densitymJyphot.flux;em.UVfloatnullablee_Fuvw2[0.18/0.9]? Uncertainty in Fuvw2mJystat.errorfloatnullableAllDisplay observation data and results of this obsID (link to Tables 2, 6 and 10)meta.ref.urlcharJ/ApJS/247/27/table4The 0.3-10keV intraday variabilities (IDVs) during 2015 December-2018 AprilrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintobsIDObservation identifier(s) (1)meta.id;obs.param;obscharMJDModified Julian Date, observation start (JD-2400000.5)dtime.epochdoubledt[0.1/24] Total length of the particular observation (2)htime.intervalfloatchi2[2.4/18089]? Reduced {chi}^2^ parameterstat.paramdoublenullabledof[1/18]? Fit degrees of freedomstat.fit.dof;stat.fit.param;meta.modelledintnullableBinOrbit segmentobs.paramcharFvar[1.5/57.2]? Fractional variability amplitude%phot.mag;arith.ratiofloatnullablee_Fvar[0.2/4]? Uncertainty in Fvar%stat.errorfloatnullablea-min[1.6/3]? Min log-parabolic parameter, astat.paramfloatnullablee_a-min[0.01/0.04]? Uncertainty in a-minstat.errorfloatnullablea-max[1.7/2.9]? Max log-parabolic parameter, astat.paramfloatnullablee_a-max[0.01/0.04]? Uncertainty in a-maxstat.errorfloatnullablealpha-min[1.0/3]? Min power-law parameter, alphastat.paramfloatnullablee_alpha-min[0.01/0.03]? Uncertainty in alpha-minstat.errorfloatnullablealpha-max[1.8/2.4]? Max power-law parameter, alphastat.paramfloatnullablee_alpha-max[0.01/0.08]? Uncertainty in alpha-maxstat.errorfloatnullableb-min[0.07/0.4]? Min curvature parameterstat.paramfloatnullablee_b-min[0.04/0.09]? Uncertainty in b-minstat.errorfloatnullableb-max[0.09/0.5]? Max curvature parameterstat.paramfloatnullablee_b-max[0.03/0.2]? Uncertainty in b-maxstat.errorfloatnullableEp-min[0.002/6.5]? Min position of the SED peakkeVstat.paramfloatnullablee_Ep-min[0.001/2]? Uncertainty in Ep-minkeVstat.errorfloatnullableEp-max[0.02/14.7]? Max position of the SED peakkeVstat.paramfloatnullablee_Ep-max[0.01/1.7]? Uncertainty in Ep-maxkeVstat.errorfloatnullableHR-min[0.1/1.1]? Minimum hardness ratiophot.flux;stat.minfloatnullablee_HR-min[0.01/0.03]? Uncertainty in HR-minstat.errorfloatnullableHR-max[0.1/1.3]? Maximum hardness ratiophot.flux;stat.maxfloatnullablee_HR-max[0.01/0.05]? Uncertainty in HR-maxstat.errorfloatnullableRemarksRemarks (3)meta.notecharJ/ApJS/247/27/table5The Optical-UV and {gamma}-ray IDVs during 2015 December-2018 AprilrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDstMJD start date of observationdtime.epochcharMJDEndMJD end date of observationdtime.epochcharBandFilter or energy rangeinstr.bandpasschardt[3.2/23.6] Length of the observation {Delta}Thtime.intervalfloatchi2Rediced {chi}^2^ parameterstat.paramfloatdofDegree of freedomstat.fit.dofintFvar[3.5/57.6] Fractional variability amplitude%phot.mag;arith.ratiofloate_Fvar[0.7/12.8] Uncertainty in Fvar%stat.errorfloatJ/ApJS/247/27/table6Results of the Swift-XRT spectral analysis with the log-parabolic modele_HR[0.01/0.05] Uncertainty in HRstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintobsID[3422805/93249013] Observation identifiermeta.id;obs.param;obsintORSOrbit/Segment code for model fit (1)obs.paramchara[1.6/3] Model parameter, photon index at the energy E1meta.code;stat.param;meta.modelledfloate_a[0.01/0.06] Uncertainty in astat.errorfloatb[0.07/0.5] Model parameter, curvature parameterstat.param;meta.modelledfloate_b[0.03/0.3] Uncertainty in bstat.errorfloatEp[0.002/14.7] Model parameter, position of the SED peakkeVstat.paramfloate_Ep[0.001/1.7] Uncertainty in EpkeVstat.errorfloat10K[0.3/9.4] Model parameter, normalization factor, x10stat.paramfloate_10K[0.01/0.2] Uncertainty in Kstat.errorfloatchi2[0.8/1.2] Reduced {chi}^2^ parameterstat.paramfloatdof[59/292] Fit degrees of freedomstat.fit.dof;stat.fit.param;meta.modelledintlogFS[12.9/269] Log unabsorbed 0.3-2keV fluxlog(mW.m**-2)phot.flux;em.X-ray.softfloate_logFS[0.2/3.8] Uncertainty in logFSlog(mW.m**-2)stat.errorfloatlogFH[2.3/291] Log unabsorbed 2-10keV fluxlog(mW.m**-2)phot.flux;em.X-ray.hardfloate_logFH[0.09/8] Uncertainty in logFHlog(mW.m**-2)stat.errorfloatlogFT[15.4/536] Log unabsorbed 0.3-10keV fluxlog(mW.m**-2)phot.flux;em.X-rayfloate_logFT[0.3/8.6] Uncertainty in logFHlog(mW.m**-2)stat.errorfloatHR[0.1/1.3] Hardness ratio (2)phot.flux;arith.ratiofloatAllDisplay observation data and results of this obsID (link to Tables 2, 6 and 10)meta.ref.urlcharJ/ApJS/247/27/table10Results of the XRT spectral analysis with a simple power-law modelrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintobsID[31202143/93249013] Observation identifiermeta.id;obs.param;obsintORSOrbit/Segment code for model (1)obs.paramcharGamma[1.7/3] Photon index in PL modelmeta.code;spect.index;meta.modelledfloate_Gamma[0.01/0.05] Uncertainty in Gammastat.errorfloatK[0.4/10] Normalizationstat.paramfloate_K[0.01/0.09] Uncertainty in Kstat.errorfloatchi2[0.8/1.2] Reduced {chi}^2^ parameterstat.paramfloatdof[68/272] Fit degrees of freedomstat.fit.dof;stat.fit.param;meta.modelledintlogFS[16.8/250] Log unabsorbed 0.3-2keV Fluxlog(mW.m**-2)phot.flux;em.X-ray.softfloate_logFS[0.2/3.3] Uncertainty in logFSlog(mW.m**-2)stat.errorfloatlogFH[4/267] Log unabsorbed 2-10keV Fluxlog(mW.m**-2)phot.flux;em.X-ray.hardfloate_logFH[0.1/6] Uncertainty in logFHlog(mW.m**-2)stat.errorfloatlogFT[10/506] Log unabsorbed 0.3-10keV Fluxlog(mW.m**-2)phot.flux;em.X-rayfloate_logFT[0.3/7] Uncertainty in logFHlog(mW.m**-2)stat.errorfloatHR[0.1/1.3] Hardness ratio (2)phot.flux;arith.ratiofloate_HR[0.01/0.05] Uncertainty in HRstat.errorfloatAllDisplay observation data and results of this obsID (link to Tables 2, 6 and 10)meta.ref.urlchar