JavaScript is disabled for your browser. Some features of this site may not work without it.
A peculiar multiwavelength flare in the blazar 3C 454.3
Gupta, A. C; Mangalam, A; Wiita, J. Paul; Kushwaha, P; Gaur, H; Zhang, H; Gu, M. F; Liao, M; Dewangan, G. C; Ho, L. C; Mohan, P; Umeura, M; Sasada, M; Volvach, A. E; Agarwal, A; Aller, M. F; Aller, H. D; Bachev, R; Lahteenmaki, A; Semkov, E; Strigachev, A; Tornikoski, M; Volvach, L. N
The blazar 3C 454.3 exhibited a strong flare seen in γ -rays, X-rays and optical/near-infrared
bands during 2009 December 3–12. Emission in the V and J bands rose more gradually than
did the γ -rays and soft X-rays, though all peaked at nearly the same time. Optical polarization
measurements showed dramatic changes during the flare, with a strong anticorrelation between
optical flux and degree of polarization (which rose from ∼3 to ∼20 per cent) during the
declining phase of the flare. The flare was accompanied by large rapid swings in polarization
angle of ∼170◦. This combination of behaviours appears to be unique. We have cm-band radio
data during the same period but they show no correlation with variations at higher frequencies.
Such peculiar behaviour may be explained using jet models incorporating fully relativistic
effects with a dominant source region moving along a helical path or by a shock-in-jet model
incorporating three-dimensional radiation transfer if there is a dominant helical magnetic
field. We find that spectral energy distributions at different times during the flare can be fit
using modified one-zone models where only the magnetic field strength and particle break
frequencies and normalizations need change. An optical spectrum taken at nearly the same
time provides an estimate for the central black hole mass of ∼2.3 × 109 M . We also consider
two weaker flares seen during the ∼200 d span over which multiband data are available. In
one of them, the V and J bands appear to lead the γ -ray and X-ray bands by a few days; in the
other, all variations are simultaneous.