A Factor Of 100: The Gamma-ray Flaring Properties Of The Blazar 3c 454.3

The blazar 3C 454.3 is the most variable and intense extragalactic gamma-ray source detected by AGILE and Fermi during the last 4 years. Its gamma-ray properties are dramatically different from what was previously known in the EGRET era. This remarkable source shows extreme flux variability (about a factor of 20) on a time-scale of 24-48 hours, as well as repeated flares on a time-scale of more than a year. The dynamic range, from the quiescence up to the most intense gamma-ray super-flare, is of about two orders of magnitude. We review the gamma-ray properties of 3C 454.3 by means of the available data, comparing both the characteristics of flares at different levels and their multi-wavelength behaviors. Moreover, an interpretation of both the long- and short-term properties of 3C 454.3 is presented, with particular emphasis on the two gamma-ray super-flares observed in 2009 and 2010, when 3C 454.3 became the brightest source of the whole gamma-ray sky.