Swift Monitoring of 3C 454.3 During a Prolonged Low Gamma-ray State
Abstract
The blazar 3C 454.3 is a well-known, extremely variable flat-spectrum radio quasar which exhibited the most intense gamma-ray flares detected up to now. Thanks to the Swift innovative and unique pointing strategy, it has been possible to monitor this source in the UV and X-ray energy bands on time-scales comparable to the ground-based optical and radio ones. The long-term multi-wavelength light-curves allowed us to obtain detailed information on time-lags between the flux emission in different energy bands, to investigate the properties of the jet during the most intense gamma-ray flares, and to study the radiation mechanisms responsible for the emission at different frequencies. In particular we found that, during extreme gamma-ray flares, the harder-when-brighter correlation noted during low and intermediate gamma-ray states does not hold anymore, leading to an achromatic increase of the X-ray flux, interpreted in terms of a balance of the synchrotron self-Compton contribution with respect to the external Compton on the disc radiation. We present our new results of an on-going Swift monitoring of 3C 454.3 during a prolonged low gamma-ray state. Our monitoring allows us to extend our study of a poorly sampled region of the X-ray spectral index vs. flux diagram, where a clear correlation between the two quantities (if any) is unclear, and improve our current understanding of this spectral trend in terms of the relative contribution of different emission components.
- Publication:
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AAS/High Energy Astrophysics Division #13
- Pub Date:
- April 2013
- Bibcode:
- 2013HEAD...1311404V