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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
earth and planetary sciences
The long-lasting activity of 3C 454.3: GASP-WEBT and satellite observations in 2008-2010
Astronomy and Astrophysics, Volume 534, Article A87, Year 2011
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Description
Context. The blazar 3C 454.3 is one of the most active sources from the radio to the γ-ray frequencies observed in the past few years. Aims. We present multiwavelength observations of this source from April 2008 to March 2010. The radio to optical data are mostly from the GASP-WEBT, UV and X-ray data from Swift, and γ-ray data from the AGILE and Fermi satellites. The aim is to understand the connection among emissions at different frequencies and to derive information on the emitting jet. Methods. Light curves in 18 bands were carefully assembled to study flux variability correlations. We improved the calibration of optical-UV data from the UVOT and OM instruments and estimated the Lyα flux to disentangle the contributions from different components in this spectral region. Results. The observations reveal prominent variability above 8 GHz. In the optical-UV band, the variability amplitude decreases with increasing frequency due to a steadier radiation from both a broad line region and an accretion disc. The optical flux reaches nearly the same levels in the 2008-2009 and 2009-2010 observing seasons; the mm one shows similar behaviour, whereas the γ and X-ray flux levels rise in the second period. Two prominent γ-ray flares in mid 2008 and late 2009 show a double-peaked structure, with a variable γ/optical flux ratio. The X-ray flux variations seem to follow the γ-ray and optical ones by about 0.5 and 1 d, respectively. Conclusions. We interpret the multifrequency behaviour in terms of an inhomogeneous curved jet, where synchrotron radiation of increasing wavelength is produced in progressively outer and wider jet regions, which can change their orientation in time. In particular, we assume that the long-term variability is due to this geometrical effect. By combining the optical and mm light curves to fit the γ and X-ray ones, we find that the γ (X-ray) emission may be explained by inverse-Comptonisation of synchrotron optical (IR) photons by their parent relativistic electrons (SSC process). A slight, variable misalignment between the synchrotron and Comptonisation zones would explain the increased γ and X-ray flux levels in 2009-2010, as well as the change in the γ/optical flux ratio during the outbursts peaks. The time delays of the X-ray flux changes after the γ, and optical ones are consistent with the proposed scenario. © 2011 ESO.
Authors & Co-Authors
Raiteri, Claudia M.
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Villata, Massimo
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Aller, M. F.
United States, Ann Arbor
University of Michigan, Ann Arbor
Gurwell, Mark A.
United States, Cambridge
Harvard-smithsonian Center for Astrophysics
Kurtanidze, Omar M.
Georgia, Abastumani
Abastumani Astrophysical Observatory
L¨ahteenm¨aki, Anne A.
Finland, Espoo
Aalto University
Larionov, Valeri M.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Russian Federation, Saint Petersburg
Pulkovo Observatory of the Russian Academy of Sciences
Romano, P.
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Vercellone, Stefano
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Agudo, Iván N.
Spain, Madrid
Consejo Superior de Investigaciones Científicas
United States, Boston
Boston University
Aller, Hugh D.
United States, Ann Arbor
University of Michigan, Ann Arbor
Arkharov, Arkady A.H.
Russian Federation, Saint Petersburg
Pulkovo Observatory of the Russian Academy of Sciences
Bach, Uwe
Germany, Bonn
Max Planck Institute for Radio Astronomy
Benítez, E.
Mexico, Mexico
Universidad Nacional Autónoma de México
Berdyugin, Andrei V.
Finland, Turku
Turun Yliopisto
Blinov, Dmitry A.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Boettcher, M.
United States, Athens
Ohio University
Bravo Calle, O. J.A.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Buemi, Carla S.
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Calcidese, Paolo
Unknown Affiliation
Carosati, Daniele
Spain, La Palma
Ept Observatories
Spain, Brena Baja
Fundación Galileo Galilei
Casas, Ricard
Spain, Barcelona
Csic - Instituto de Ciencias Del Espacio Ice
Chen, Wenping
Taiwan, Taoyuan
National Central University
Efimova, Natalia V.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Russian Federation, Saint Petersburg
Pulkovo Observatory of the Russian Academy of Sciences
Gómez, Jose L.
Spain, Madrid
Consejo Superior de Investigaciones Científicas
Gusbar, Courtney
United States, Athens
Ohio University
Hawkins, Keith
United States, Athens
Ohio University
Heidt, Jochen
Germany, Heidelberg
Landessternwarte Heidelberg
Hiriart, David
Mexico, Mexico
Universidad Nacional Autónoma de México
Hsiao, Hsiangyao
Taiwan, Taoyuan
National Central University
Jorstad, Svetlana G.
Russian Federation, Saint Petersburg
Saint Petersburg State University
United States, Boston
Boston University
Joshi, Manasvita
United States, Boston
Boston University
Kimeridze, Givi N.
Georgia, Abastumani
Abastumani Astrophysical Observatory
Koptelova, Ekaterina A.
Taiwan, Taoyuan
National Central University
Taiwan, Taipei
National Taiwan University
Grishina, Tatiana S.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Kopatskaya, Evgenia N.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Kurtanidze, Sofia O.
Georgia, Abastumani
Abastumani Astrophysical Observatory
Larionova, Elena G.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Larionova, Liudmilla V.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Leto, Paolo
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Ligustri, Rolando
Unknown Affiliation
Lindfors, Elina J.
Finland, Turku
Turun Yliopisto
Lister, Matthew L.
United States, West Lafayette
Purdue University
Marscher, Alan P.
United States, Boston
Boston University
Molina, Sol N.
Spain, Madrid
Consejo Superior de Investigaciones Científicas
Morozova, Daria A.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Nieppola, Elina
Finland, Espoo
Aalto University
Finland, Turku
Turun Yliopisto
Nikolashvili, M. G.
Georgia, Abastumani
Abastumani Astrophysical Observatory
Nilsson, Kari
Finland, Turku
Turun Yliopisto
Palma, N. I.
United States, Athens
Ohio University
Honduras, Tegucigalpa
Universidad Nacional Autónoma de Honduras
Pasanen, Mikko
Finland, Turku
Turun Yliopisto
Reinthal, Riho
Finland, Turku
Turun Yliopisto
Ros, J. A.
Unknown Affiliation
Roustazadeh, Parisa
United States, Athens
Ohio University
Sadun, Alberto C.
United States, Denver
University of Colorado Denver
Sakamoto, Takanori
United States, Washington, D.c.
National Aeronautics and Space Administration
Schwartz, Richard D.
United States, Sequim
Galaxy View Observatory
Sigua, Lorand A.
Georgia, Abastumani
Abastumani Astrophysical Observatory
Sillanp̈äa, Aimo K.
Finland, Turku
Turun Yliopisto
Takalo, Leo O.
Finland, Turku
Turun Yliopisto
Tammi, Joni
Finland, Espoo
Aalto University
Taylor, Brian W.
United States, Boston
Boston University
United States, Flagstaff
Lowell Observatory
Tornikoski, Merja
Finland, Espoo
Aalto University
Trigilio, Corrado
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Troitsky, Ivan S.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Umana, Grazia
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Volvach, A. E.
Ukraine, Bakhchysarai
Crimean Astrophysical Observatory Ras
Statistics
Citations: 70
Authors: 67
Affiliations: 27
Identifiers
Doi:
10.1051/0004-6361/201117026
ISSN:
00046361
Research Areas
Cancer
Environmental