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Verfasst von:Raiteri, Claudia Maria [VerfasserIn]   i
 Kurtanidze, Omar M. [VerfasserIn]   i
Titel:Blazar spectral variability as explained by a twisted inhomogeneous jet
Verf.angabe:C.M. Raiteri, M. Villata, J.A. Acosta-Pulido, I. Agudo, A.A. Arkharov, R. Bachev, G.V. Baida, E. Benítez, G.A. Borman, W. Boschin, V. Bozhilov, M.S. Butuzova, P. Calcidese, M.I. Carnerero, D. Carosati, C. Casadio, N. Castro-Segura, W.-P. Chen, G. Damljanovic, F. D’Ammando, A. Di Paola, J. Echevarría, N.V. Efimova, Sh. A. Ehgamberdiev, C. Espinosa, A. Fuentes, A. Giunta, J.L. Gómez, T.S. Grishina, M.A. Gurwell, D. Hiriart, H. Jermak, B. Jordan, S.G. Jorstad, M. Joshi, E.N. Kopatskaya, K. Kuratov, O.M. Kurtanidze, S.O. Kurtanidze, A. Lähteenmäki, V.M. Larionov, E.G. Larionova, L.V. Larionova, C. Lázaro, C.S. Lin, M.P. Malmrose, A.P. Marscher, K. Matsumoto, B. McBreen, R. Michel, B. Mihov, M. Minev, D.O. Mirzaqulov, A.A. Mokrushina, S.N. Molina, J.W. Moody, D.A. Morozova, S.V. Nazarov, M.G. Nikolashvili, J.M. Ohlert, D.N. Okhmat, E. Ovcharov, F. Pinna, T.A. Polakis, C. Protasio, T. Pursimo, F.J. Redondo-Lorenzo, N. Rizzi, G. Rodriguez-Coira, K. Sadakane, A.C. Sadun, M.R. Samal, S.S. Savchenko, E. Semkov, B.A. Skiff, L. Slavcheva-Mihova, P.S. Smith, I.A. Steele, A. Strigachev, J. Tammi, C. Thum, M. Tornikoski, Yu. V. Troitskaya, I.S. Troitsky, A.A. Vasilyev, O. Vince
E-Jahr:2017
Jahr:4 December 2017
Umfang:13 S.
Fussnoten:Gesehen am 08.08.2018
Titel Quelle:Enthalten in: Nature <London>
Ort Quelle:London [u.a.] : Nature Publ. Group, 1869
Jahr Quelle:2017
Band/Heft Quelle:552(2017), 7685, Seite 374-377
ISSN Quelle:1476-4687
Abstract:Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming1. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles2, with possible intervention of shock waves3,4 or turbulence5. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events6,7,8,9,10 and can also explain specific properties of blazar emission, such as intra-day variability11, quasi-periodicity12,13 and the delay of radio flux variations relative to optical changes14. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions—such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution—can explain snapshots of the spectral behaviour of blazars in many cases15,16. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities17 or rotation of the twisted jet6 cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.
DOI:doi:10.1038/nature24623
URL:Bitte beachten Sie: Dies ist ein Bibliographieeintrag. Ein Volltextzugriff für Mitglieder der Universität besteht hier nur, falls für die entsprechende Zeitschrift/den entsprechenden Sammelband ein Abonnement besteht oder es sich um einen OpenAccess-Titel handelt.

Volltext ; Verlag: http://dx.doi.org/10.1038/nature24623
 Volltext: https://www.nature.com/articles/nature24623
 DOI: https://doi.org/10.1038/nature24623
Datenträger:Online-Ressource
Sprache:eng
K10plus-PPN:1578356237
Verknüpfungen:→ Zeitung

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