The WEBT Campaign on the Blazar 3C 279 in 2006

• DOI: 10.1086/522583
• Publication Date: 2007-12-05T07:08:24Z
• Authors: M. Bottcher; S. Basu; M. Joshi; M. Villata; A. Arai; N. Aryan; I. M. Asfandiyarov; U. Bach; R. Bachev; A. Berduygin; M. Blaek; C. Buemi; A. J. Castro‐Tirado; A. De Ugarte Postigo; A. Frasca; L. Fuhrmann; V. A. Hagen‐Thorn; G. Henson; T. Hovatta; R. Hudec; M. Ibrahimov; Y. Ishii; R. Ivanidze; M. Jelinek; M. Kamada; B. Kapanadze; M. Katsuura; D. Kotaka; Y. Y. Kovalev; Yu. A. Kovalev; P. Kubanek; M. Kurosaki; O. Kurtanidze; A. Lahteenmaki; L. Lanteri; V. M. Larionov; L. Larionova; C.‐U. Lee; P. Leto; E. Lindfors; E. Marilli; K. Marshall; H. R. Miller; M. G. Mingaliev; N. Mirabal; S. Mizoguchi; K. Nakamura; E. Nieppola; M. Nikolashvili; K. Nilsson; S. Nishiyama; J. Ohlert; M. A. Osterman; S. Pak; M. Pasanen; C. S. Peters; T. Pursimo; C. M. Raiteri; J. Robertson; T. Robertson; W. T. Ryle; K. Sadakane; A. Sadun; L. Sigua; B.‐W. Sohn; A. Strigachev; N. Sumitomo; L. O. Takalo; Y. Tamesue; K. Tanaka; J. R. Thorstensen; G. Tosti; C. Trigilio; G. Umana; S. Vennes; S. Vitek; A. Volvach; J. Webb; M. Yamanaka; H.‐S. Yim
• Keywords: Flare; Spectral slope; Exponential decay

The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio by Whole Earth Blazar Telescope (WEBT) collaboration organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra INTEGRAL in mid-January, additional coverage RXTE Swift XRT. In this paper we focus on results WEBT campaign. source exhibited substantial variability optical flux spectral shape, a characteristic timescale few days. patterns throughout BVRI bands were very closely correlated each other, while there no obvious correlation between radio variability. After ToO trigger, underwent remarkably clean quasi-exponential decay about 1 mag, τd ~ 12.8 intriguing contrast to other (in particular, BL Lac type) blazars, find lag shorter wavelength behind longer RVB ranges, time delay increasing frequency. Spectral hardening during flares appears delayed respect rising flux. This, combination steep IR-optical continuum index α0 1.5-2.0, may indicate highly oblique magnetic field configuration near base jet, leading inefficient particle acceleration electron injection spectrum. alternative explanation slow (timescale several days) mechanism would require unusually low B ≲ 0.2 G, order magnitude lower than inferred previous analyses simultaneous SEDs flat-spectrum quasars similar properties.