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dc.contributor.authorLarionov, V. M.*
dc.contributor.authorVillata, M.*
dc.contributor.authorRaiteri, C. M.*
dc.contributor.authorJorstad, S. G.*
dc.contributor.authorMarscher, A. P.*
dc.contributor.authorAgudo, I.*
dc.contributor.authorSmith, P. S.*
dc.contributor.authorAcosta-Pulido, J. A.*
dc.contributor.author˙arévalo, M. J.*
dc.contributor.authorArkharov, A. A.*
dc.contributor.authorBachev, R.*
dc.contributor.authorBlinov, D. A.*
dc.contributor.authorBorisov, G.*
dc.contributor.authorBorman, G. A.*
dc.contributor.authorBozhilov, V.*
dc.contributor.authorBueno, A.*
dc.contributor.authorCarnerero, M. I.*
dc.contributor.authorCarosati, D.*
dc.contributor.authorCasadio, C.*
dc.contributor.authorChen, W. P.*
dc.contributor.authorClemens, D. P.*
dc.contributor.authorDi Paola, A.*
dc.contributor.authorEhgamberdiev, Sh. A.*
dc.contributor.authorGómez, J. L.*
dc.contributor.authorGonzález-Morales, P. A.*
dc.contributor.authorGriñón-Marín, A.*
dc.contributor.authorGrishina, T. S.*
dc.contributor.authorHagen-Thorn, V. A.*
dc.contributor.authorIbryamov, S.*
dc.contributor.authorItoh, R.*
dc.contributor.authorJoshi, M.*
dc.contributor.authorKopatskaya, E. N.*
dc.contributor.authorKoptelova, E.*
dc.contributor.authorLázaro, C.*
dc.contributor.authorLarionova, E. G.*
dc.contributor.authorLarionova, L. V.*
dc.contributor.authorManilla-Robles, A.*
dc.contributor.authorMetodieva, Y.*
dc.contributor.authorMilanova, Yu. V.*
dc.contributor.authorMirzaqulov, D. O.*
dc.contributor.authorMolina, S. N.*
dc.contributor.authorMorozova, D. A.*
dc.contributor.authorNazarov, S. V.*
dc.contributor.authorOvcharov, E.*
dc.contributor.authorPeneva, S.*
dc.contributor.authorRos, J. A.*
dc.contributor.authorSadun, A. C.*
dc.contributor.authorSavchenko, S. S.*
dc.contributor.authorSemkov, E.*
dc.contributor.authorSergeev, S. G.*
dc.contributor.authorStrigachev, A.*
dc.contributor.authorTroitskaya, Yu. V.*
dc.contributor.authorTroitsky, I. S.*
dc.date.accessioned2016-12-16T00:13:07Z
dc.date.available2016-12-16T00:13:07Z
dc.date.issued2016-09-21
dc.identifier.citationExceptional outburst of the blazar CTA 102 in 2012: the GASP–WEBT campaign and its extension 2016, 461 (3):3047 Monthly Notices of the Royal Astronomical Societyen
dc.identifier.issn0035-8711
dc.identifier.issn1365-2966
dc.identifier.doi10.1093/mnras/stw1516
dc.identifier.urihttp://hdl.handle.net/10150/621728
dc.description.abstractAfter several years of quiescence, the blazar CTA 102 underwent an exceptional outburst in 2012 September-October. The flare was tracked from gamma-ray to near-infrared (NIR) frequencies, including Fermi and Swift data as well as photometric and polarimetric data from several observatories. An intensive Glast-Agile support programme of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration campaign in optical and NIR bands, with an addition of previously unpublished archival data and extension through fall 2015, allows comparison of this outburst with the previous activity period of this blazar in 2004-2005. We find remarkable similarity between the optical and gamma-ray behaviour of CTA 102 during the outburst, with a time lag between the two light curves of approximate to 1 h, indicative of cospatiality of the optical and gamma-ray emission regions. The relation between the gamma-ray and optical fluxes is consistent with the synchrotron self-Compton (SSC) mechanism, with a quadratic dependence of the SSC gamma -ray flux on the synchrotron optical flux evident in the post-outburst stage. However, the gamma -ray/optical relationship is linear during the outburst; we attribute this to changes in the Doppler factor. A strong harder-when-brighter spectral dependence is seen both the in gamma-ray and optical non-thermal emission. This hardening can be explained by convexity of the UV-NIR spectrum that moves to higher frequencies owing to an increased Doppler shift as the viewing angle decreases during the outburst stage. The overall pattern of Stokes parameter variations agrees with a model of a radiating blob or shock wave that moves along a helical path down the jet.
dc.description.sponsorshipRussian RFBR [15-02-00949]; St. Petersburg University [6.38.335.2015, 6.42.1113.2016]; NASA [NNX08AV65G, NNX10AO59G, NNX10AU15G, NNX11AO37G, NNX11AQ03G, NNX14AQ58G, NNX09AU10G, NNX12AO93G]; Spanish Ministry of Economy and Competitiveness (MINECO) [AYA2013-40825-P]; MINECO; NSF; BU; Lowell Observatory; Bulgarian Ministry of Education and Sciences [DO 02-137 (BIn-13/09)]; Uzbekistan Academy of Sciences [F2-FA-F027]en
dc.language.isoenen
dc.publisherOXFORD UNIV PRESSen
dc.relation.urlhttp://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stw1516en
dc.rights© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Societyen
dc.subjectmethods: observationalen
dc.subjecttechniques: photometricen
dc.subjecttechniques: polarimetricen
dc.subjectgalaxies: activeen
dc.subjectquasars: individual: CTA 102en
dc.titleExceptional outburst of the blazar CTA 102 in 2012: the GASP–WEBT campaign and its extensionen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Steward Observen
dc.identifier.journalMonthly Notices of the Royal Astronomical Societyen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-09-11T16:22:18Z
html.description.abstractAfter several years of quiescence, the blazar CTA 102 underwent an exceptional outburst in 2012 September-October. The flare was tracked from gamma-ray to near-infrared (NIR) frequencies, including Fermi and Swift data as well as photometric and polarimetric data from several observatories. An intensive Glast-Agile support programme of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration campaign in optical and NIR bands, with an addition of previously unpublished archival data and extension through fall 2015, allows comparison of this outburst with the previous activity period of this blazar in 2004-2005. We find remarkable similarity between the optical and gamma-ray behaviour of CTA 102 during the outburst, with a time lag between the two light curves of approximate to 1 h, indicative of cospatiality of the optical and gamma-ray emission regions. The relation between the gamma-ray and optical fluxes is consistent with the synchrotron self-Compton (SSC) mechanism, with a quadratic dependence of the SSC gamma -ray flux on the synchrotron optical flux evident in the post-outburst stage. However, the gamma -ray/optical relationship is linear during the outburst; we attribute this to changes in the Doppler factor. A strong harder-when-brighter spectral dependence is seen both the in gamma-ray and optical non-thermal emission. This hardening can be explained by convexity of the UV-NIR spectrum that moves to higher frequencies owing to an increased Doppler shift as the viewing angle decreases during the outburst stage. The overall pattern of Stokes parameter variations agrees with a model of a radiating blob or shock wave that moves along a helical path down the jet.


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