Optical and radio behaviour of the BL Lacertae object 0716+714 ⋆
C. M. Raiteri,M. Villata,Gino Tosti,Roberto Nesci,E. Massaro,Margo F. Aller,H. D. Aller,Harri Teräsranta,O. M. Kurtanidze,Maria G. Nikolashvili,Mansur Ibrahimov,Mansur Ibrahimov,I. E. Papadakis,I. E. Papadakis,Thomas P. Krichbaum,Alex Kraus,A. Witzel,H. Ungerechts,Ute Lisenfeld,U. Bach,Giuseppe Cimo,S. Ciprini,Lars Fuhrmann,G. N. Kimeridze,L. Lanteri,M. Maesano,F. Montagni,Giuliano Nucciarelli,L. Ostorero +28 more
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In this article, the authors presented a wide optical and radio database of the BL Lac object 0716+714, which consists of 4854 data points collected in the UBVRI bands since 1994, while radio light curves extend back to 1978.Abstract:
Eight optical and four radio observatories have been intensively monitoring the BL Lac object 0716+714 in the last years: 4854 data points have been collected in the UBVRI bands since 1994, while radio light curves extendback to 1978. Many of these data, which all together constitute the widest optical and radio database available on this object, are presented here for the first time. Four major optical outbursts were observed at the beginning of 1995, in late 1997, at the end of 2000, and in fall 2001. In particular, an exceptional brightening of 2.3 mag in 9 days was detected in the R band just before the BeppoSAX pointing of October 30, 2000. A big radio outburst lasted from early 1998 to the end of 1999. The long-term trend shown by the optical light curves seems to vary with a characteristic time scale of about 3.3 years, while a longer period of 5.5-6 years seems to characterize the radio long-term variations. In general, optical colour indices are only weakly correlated with brightness; a clear spectral steepening trend was observed during at least one long-lasting dimming phase. Moreover, the optical spectrum became steeper after JD ∼ 2451 000, the change occurring in the decaying phase of the late-1997 outburst. The radio flux behaviour at different frequencies is similar, but the flux variation amplitude decreases with increasing wavelength. The radio spectral index varies with brightness (harder when brighter), but the radio fluxes seem to be the sum of two different-spectrum contributions: a steady base level and a harder-spectrum variable component. Once the base level is removed, the radio variations appear as essentially achromatic, similarly to the optical behaviour. Flux variations at the higher radio frequencies lead the lower-frequency ones with week-month time scales. The behaviour of the optical and radio light curves is quite different, the broad radio outbursts not corresponding in time to the faster optical ones and the cross-correlation analysis indicating only weak correlation with long time lags. However, minor radio flux enhancements simultaneous with the major optical flares can be recognized, which may imply that the mechanism producing the strong flux increases in the optical band also marginally affects the radio one. On the contrary, the process responsible for the big radio outbursts does not seem to affect the optical emission.read more
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Multi-colour optical monitoring of eight red blazars
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Results of WEBT, VLBA and RXTE monitoring of 3C 279 during 2006-2007 ⋆
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The Outburst of the Blazar S5 0716+71 in 2011 October: Shock in a Helical Jet
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TL;DR: The results of optical (R band) photometric and polarimetric monitoring and Very Long Baseline Array (VLBA) imaging of the blazar S5 0716+714 along with Fermi?-ray data during a multi-waveband outburst in 2011 October are presented in this article.
Journal ArticleDOI
Multifrequency monitoring of the blazar 0716+714 during the GASP-WEBT-AGILE campaign of 2007
M. Villata,C. M. Raiteri,Valeri M. Larionov,Valeri M. Larionov,Omar M. Kurtanidze,K. Nilsson,Margo F. Aller,Merja Tornikoski,A. E. Volvach,Hugh D. Aller,Arkady A. Arkharov,Uwe Bach,P. Beltrame,Gopal Bhatta,Carla Buemi,Markus Böttcher,P. Calcidese,D. Carosati,A. J. Castro-Tirado,D. da Rio,A. Di Paola,Mauro Dolci,E. Forné,Antonio Frasca,Vladimir A. Hagen-Thorn,Jochen Heidt,David Hiriart,Martin Jelínek,Givi N. Kimeridze,Tatiana S. Konstantinova,E. N. Kopatskaya,L. Lanteri,Paolo Leto,R. Ligustri,Elina Lindfors,Anne Lähteenmäki,E. Marilli,E. Nieppola,M. G. Nikolashvili,M. Pasanen,B. Ragozzine,J. A. Ros,Lorand A. Sigua,Richard L. Smart,M. Sorcia,L. O. Takalo,Marco Tavani,Corrado Trigilio,R. Turchetti,Kyle Uckert,G. Umana,S. Vercellone,James R. Webb +52 more
TL;DR: In this paper, the authors presented the GASP-WEBT optical and radio light curves of this blazar obtained in July-November 2007, about various AGILE pointings at the source.
Journal ArticleDOI
Periodic oscillations in the intra-day optical light curves of the blazar s5 0716+714
TL;DR: In this paper, the authors present the results of a periodicity search of 20 intra-day variable optical light curves of the blazar S5 0716+714, selected from a database of 102 light curves spanning over three years.
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