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A new activity phase of the blazar 3C 454.3. Multifrequency observations by the WEBT and XMM-Newton in 2007-2008

hal.structure.identifierINAF - Osservatorio Astrofisico di Torino [OATo]
dc.contributor.authorRAITERI, C. M.
hal.structure.identifierINAF - Osservatorio Astrofisico di Torino [OATo]
dc.contributor.authorVILLATA, M.
dc.contributor.authorLARIONOV, V. M.
dc.contributor.authorGURWELL, M. A.
hal.structure.identifierShanghai Institute of Ceramics
dc.contributor.authorCHEN, W. P.
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorCHARLOT, P.
dc.date.issued2008
dc.identifier.issn0004-6361
dc.description.abstractEnWe present and analyse the WEBT multifrequency observations of 3C 454.3 in the 2007-2008 observing season, including XMM-Newton observations and near-IR spectroscopic monitoring, and compare the recent emission behaviour with the past one. In the optical band we observed a multi-peak outburst in July-August 2007, and other faster events in November 2007 - February 2008. During these outburst phases, several episodes of intranight variability were detected. A mm outburst was observed starting from mid 2007, whose rising phase was contemporaneous to the optical brightening. A slower flux increase also affected the higher radio frequencies, the flux enhancement disappearing below 8 GHz. The analysis of the optical-radio correlation and time delays, as well as the behaviour of the mm light curve, confirm our previous predictions, suggesting that changes in the jet orientation likely occurred in the last few years. The historical multiwavelength behaviour indicates that a significant variation in the viewing angle may have happened around year 2000. Colour analysis reveals a complex spectral behaviour, which is due to the interplay of different emission components. All the near-IR spectra show a prominent Halpha emission line, whose flux appears nearly constant. The analysis of the XMM-Newton data indicates a correlation between the UV excess and the soft-X-ray excess, which may represent the head and the tail of the big blue bump, respectively. The X-ray flux correlates with the optical flux, suggesting that in the inverse-Compton process either the seed photons are synchrotron photons at IR-optical frequencies or the relativistic electrons are those that produce the optical synchrotron emission. The X-ray radiation would thus be produced in the jet region from where the IR-optical emission comes.
dc.language.isoen
dc.publisherEDP Sciences
dc.subjectgalaxies: jets
dc.title.enA new activity phase of the blazar 3C 454.3. Multifrequency observations by the WEBT and XMM-Newton in 2007-2008
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361:200810869
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.identifier.arxiv0810.2424
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.page755-766
bordeaux.volume491
bordeaux.issue3
bordeaux.peerReviewedoui
hal.identifierhal-00402933
hal.version1
hal.popularnon
hal.audienceInternationale
dc.subject.esgalaxies: active
dc.subject.esgalaxies: quasars: general
dc.subject.esgalaxies: quasars: individual: 3C 454.3
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00402933v1
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