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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
earth and planetary sciences
The whole earth blazar telescope campaign on the intermediate BL Lac object 3C 66A in 2007-2008
Astrophysical Journal, Volume 694, No. 1, Year 2009
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Description
Prompted by a high optical state in 2007 September, the Whole Earth Blazar Telescope consortium organized an intensive optical, near-IR (JHK) and radio observing campaign on the intermediate BL Lac object 3C 66A throughout the fall and winter of 2007-2008. In this paper, we present data from 28 observatories in 12 countries, covering the observing season from late 2007 July through 2008 February. The source remained in a high optical state throughout the observing period and exhibited several bright flares on timescales of 10 days. This included an exceptional outburst around 2007 September 15-20, reaching a peak brightness at R 13.4. Our campaign revealed microvariability with flux changes up to |dR/dt| 0.02 mag hr-1. Our observations do not reveal evidence for systematic spectral variability in the overall high state covered by our campaign, in agreement with previous results. In particular, we do not find evidence for spectral hysteresis in 3C 66A for which hints were found in an earlier campaign in a somewhat lower flux state. We also did not find any evidence for spectral lags in the discrete correlation functions between different optical bands. We infer a value of the magnetic field in the emission region of B 19 e 2/7 B τ-6/7 h D 13/7 1 G, where eB is the magnetic field equipartition fraction, τh is the shortest observed variability timescale in units of hours, and D 1 is the Doppler factor in units of 10. From the lack of systematic spectral variability, we can derive an upper limit on the Doppler factor, D ≤ 28 τ-1/8 h e 3/16 B. This is in perfect agreement with superluminal motion measurements with the VLBI/VLBA of βapp ≤ 27 and argues against models with very high Lorentz factors of Γ ≳ 50, required for a one-zone synchrotron-self-Compton interpretation of some high-frequency-peaked BL Lac objects detected at TeV γ-ray energies. © 2009 The American Astronomical Society.
Authors & Co-Authors
Boettcher, M.
United States, Athens
Ohio University
Aller, Hugh D.
United States, Ann Arbor
University of Michigan, Ann Arbor
Aller, M. F.
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
Bachev, Rumen S.
Bulgaria, Sofia
The Bulgarian Academy of Sciences
Berdyugin, Andrei V.
Finland, Turku
Turun Yliopisto
Buemi, Carla S.
Italy, Catania
Osservatorio Astrofisico Di Catania
Calcidese, Paolo
Italy, Nus
Osservatorio Astronomico Della Regione Autonoma Valle D'aosta
Carosati, Daniele
Unknown Affiliation
Charlot, Patrick
France, Bordeaux
Université de Bordeaux
France, Paris
Cnrs Centre National de la Recherche Scientifique
Ciprini, Stefano
Italy, Perugia
Università Degli Studi Di Perugia
Di Paola, Andrea
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Efimova, Natalia V.
Russian Federation, Saint Petersburg
Pulkovo Observatory of the Russian Academy of Sciences
Frasca, Antonio
Italy, Catania
Osservatorio Astrofisico Di Catania
Gupta, Alok Chandra
India, Nainital
Aryabhatta Research Institute of Observational Sciences
Heidt, Jochen
Germany, Heidelberg
Landessternwarte Heidelberg
Hiriart, David
Mexico, Mexico
Universidad Nacional Autónoma de México
Grishina, Tatiana S.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Kopatskaya, Evgenia N.
Russian Federation, Saint Petersburg
Saint Petersburg State University
L¨ahteenm¨aki, Anne A.
Finland, Espoo
Aalto University
Lanteri, Luciano
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Larionov, Valeri M.
Russian Federation, Saint Petersburg
Saint Petersburg State University
Russian Federation, Saint Petersburg (ex Leningrad)
Isaac Newton Institute of Chile
Le Campion, Jean François
France, Bordeaux
Université de Bordeaux
France, Paris
Cnrs Centre National de la Recherche Scientifique
Leto, Paolo
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Lindfors, Elina J.
Finland, Turku
Turun Yliopisto
Nieppola, Elina
Finland, Espoo
Aalto University
Nilsson, Kari
Finland, Turku
Turun Yliopisto
Pääkkönen, Pertti
Finland, Kuopio
Itä-suomen Yliopisto
Pasanen, Mikko
Finland, Turku
Turun Yliopisto
Raiteri, Claudia M.
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Ros, J. A.
Spain, Sabadell
Agrupación Astronómica de Sabadell
Sadun, Alberto C.
United States, Denver
University of Colorado Denver
Sánchez, Albert
Unknown Affiliation
Semkov, Evgeni H.
Bulgaria, Sofia
The Bulgarian Academy of Sciences
Strigachev, Anton A.
Bulgaria, Sofia
The Bulgarian Academy of Sciences
Takalo, Leo O.
Finland, Turku
Turun Yliopisto
Tornikoski, Merja
Finland, Espoo
Aalto University
Trigilio, Corrado
Italy, Catania
Osservatorio Astrofisico Di Catania
Umana, Grazia
Italy, Catania
Osservatorio Astrofisico Di Catania
Valcheva, Antoniya T.
Bulgaria, Sofia
The Bulgarian Academy of Sciences
Villata, Massimo
Italy, Rome
Istituto Nazionale Di Astrofisica, Rome
Volvach, A. E.
Ukraine, Bakhchysarai
Crimean Astrophysical Observatory Ras
Wu, Jianghua
China, Beijing
Chinese Academy of Sciences
Zhou, X. U.
China, Beijing
Chinese Academy of Sciences
Statistics
Citations: 38
Authors: 45
Affiliations: 24
Identifiers
Doi:
10.1088/0004-637X/694/1/174
ISSN:
0004637X
Research Areas
Environmental