Multiwavelength Observations of a Dramatic High‐Energy Flare in the Blazar 3C 279

Abstract

The blazar 3C 279, one of the brightest identified extragalactic objects in the γ-ray sky, underwent a large (factor of ∼10 in amplitude) flare in γ-rays towards the end of a 3-week pointing by CGRO, in 1996 January-February. The flare peak represents the highest γ-ray intensity ever recorded for this object. During the high state, extremely rapid γ-ray variability was seen, including an increase of a factor of 2.6 in ∼8 hr, which strengthens the case for relativistic beaming. Coordinated multifrequency observations were carried out with RXTE, ASCA, ROSAT and IUE and from many ground-based observatories, covering most accessible wavelengths. The well-sampled, simultaneous RXTE light curve shows an outburst of lower amplitude (factor of ≃3) well correlated with the γ-ray flare without any lag larger than the temporal resolution of ∼1 day. The optical-UV light curves, which are not well sampled during the high energy flare, exhibit more modest variations (factor of ∼2) and a lower degree of correlation. The flux at millimetric wavelengths was near an historical maximum during the γ-ray flare peak and there is a suggestion of a correlated decay. We present simultaneous spectral energy distributions of 3C 279 prior to and near to the flare peak. The γ-rays vary by more than the square of the observed IR-optical Stanford, CA 94305

Core shift effect in blazars

“…It displays violent multiwavelength flux variability and is well studied by various observation programs (e.g. Maraschi et al 1994;Wehrle et al 1998;Lindfors et al 2006, Collmar et al 2007. Flux variability at X-rays, R band and 14.5 GHz frequency band have been found to be significantly correlated, suggesting a possible co-spatial origin.…”

Spectral Energy Distributions of 3C 279 Revisited:BeppoSAXObservations and Variability Models

“…The solid line is a sum of all the contributions. Simultaneous data are from Wehrle et al (1998). on organized campaigns with wide multiwavelength coverage (1993 and 1996 preÑare and Ñare).…”

“…1996.ÈThroughout this second multiwavelength campaign, 3C 279 was in a high state, similar to that of 1991 ; during the observation there was an extraordinary Ñare lasting 2È3 days, particularly intense in the c-ray band. Following Wehrle et al (1998), we divided the light curve in two parts, averaging the observed Ñuxes in the period January 24È28 preceding the Ñare, and in a 2 day window centered on the c-ray peak. The resulting SEDs are shown in Figure 4.…”

Comptonization of Infrared Radiation from Hot Dust by Relativistic Jets in Quasars

“…In part, the SSC process may be important in the soft/mid-energy X-ray bands (Inoue & Takahara 1996 ;Kubo et al 1998). Furthermore, X-ray variability usually shows lower amplitude than variability in the c-ray band (Sambruna 1997 ;Wehrle et al 1998). This suggests that X-rays produced Vol.…”