The WEBT Campaign on the Blazar 3C279 in 2006

Abstract

The quasar 3C279 was the target of an extensive multiwavelength monitoring campaign from January through April 2006, including an optical-IR-radio monitoring campaign by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we focus on the results of the WEBT campaign. The source exhibited substantial variability of optical flux and spectral shape, with a characteristic time scale of a few days. The variability patterns throughout the optical BVRI bands were very closely correlated with each other. In intriguing contrast to other (in particular, BL Lac type) blazars, we find a lag of shorter- behind longer-wavelength variability throughout the RVB ranges, with a time delay increasing with increasing frequency. Spectral hardening during flares appears delayed with respect to a rising optical flux. This, in combination with the very steep IR-optical continuum spectral index of ~ 1.5 - 2.0, may indicate a highly oblique magnetic field configuration near the base of the jet. An alternative explanation through a slow (time scale of several days) acceleration mechanism would require an unusually low magnetic field of < 0.2 G, about an order of magnitude lower than inferred from previous analyses of simultaneous SEDs of 3C279 and other FSRQs with similar properties.

Accepted for publication in ApJ

References in corpus (4)

• The VLBA Imaging and Polarimetry Survey at 5 GHz
• The host galaxies of luminous quasars
• Does the Blazar Gamma-Ray Spectrum Harden with Increasing Flux? Analysis of 9 Years of EGRET Data
• The Multiple Timescales of Optical Variability of the Blazar 3C 279 During the 2001-2002 Outburst

Cited by in corpus (9)

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• Radio-to-UV monitoring of AO 0235+164 by the WEBT and Swift during the 2006--2007 outburst
• Absorption of 10 Gev--1 Tev Gamma Rays by Radiation from Broad-Line Region in 3C 279
• An original constraint on the Hubble constant: h>0.74
• Patterns of variability in gamma-ray blazars
• Optical Variability of the Radio Source J 1128+5925 -- II. Confirmation of its Optical Quietness