Related papers: Gamma-Ray Flares in Long Term Light Curve of 3C 45…
I present a systematic study of gamma-ray flares in blazars. For this purpose, I propose a very simple and practical definition of a flare as a period of time, associated with a given flux peak, during which the flux is above half of the…
Recently, blazar 4C +27.50 was found to be flaring in gamma-rays since its detection with Fermi-LAT in 2008. For the first time, a dedicated temporal and spectral study of the blazar 4C +27.50 has been performed in this work to understand…
The results of a long-term multiwavelength study of the powerful flat spectrum radio quasar 3C 454.3 using {\it Fermi}-LAT and Swift XRT/UVOT data are reported. In the $\gamma$-ray band, {\it Fermi}-LAT observations show several major…
The blazar 4C 31.03 recently underwent a major gamma-ray outburst at the beginning of 2023 after a prolonged quiescent phase. Fermi-LAT reported a daily average flux of 5x10^-6 phs cm^-2 s^-1, which is about 60 times its average value. We…
4C+28.07 is a $\gamma$-ray Flat Spectrum Radio Quasar (FSRQ) type source. It is often monitored at different frequencies, though long-term multi-wavelength data of this source have not been modelled in detail before. We have analyzed $\sim…
We present a \gamma-ray photon flux and spectral variability study of the flat-spectrum radio quasar 3C 273 over a rapid flaring activity period between September 2009 to April 2010. Five major flares are observed in the source during this…
3C 454.3 is the most variable and intense extragalactic gamma-ray blazar detected by AGILE and Fermi during the last 4 years. This remarkable source shows extreme flux variability (about a fact or of 20) on a time-scale of 24-48 hours, as…
This is the first report of Fermi Gamma-ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope (LAT), covering 2008 July 7 -…
A multiwavelength temporal and spectral analysis of flares of 3C 279 during November 2017--July 2018 are presented in this work. Three bright gamma-ray flares were observed simultaneously in X-ray and Optical/UV along with a prolonged…
We focus on the exceptional flaring activity of 3C 454.3 in November 2010 and we discuss a theoretical framework addressing all data in their overall evolution. For two weeks the source has shown a plateau of enhanced GeV emission preceding…
We search through $\gamma$-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope and find 24 blazars (or candidates) that have a single clear flare event in their 9.5 year long-term light curves.…
Characterisation of the long-term variations in the broad line region in a luminous blazar, where Comptonisation of broad-line emission within a relativistic jet is the standard scenario for production of gamma-ray emission that dominates…
In May - July 2014, the flat spectrum radio quasar 3C 454.3 exhibited strong flaring behaviour. Observations with the Large Area Telescope detector on-board the Fermi Gamma-ray Space Telescope captured the $\gamma$-ray flux at energies 0.1…
The flat spectrum radio quasar 3C~454.3 underwent an extraordinary outburst in December 2009 when it became the brightest gamma-ray source in the sky for over one week. Its daily flux measured with the Fermi Large Area Telescope at photon…
We present the detections of 19 solar flares detected in high-energy gamma rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first four years of operation. Interestingly, all flares are associated with fairly fast…
We present the light curves and spectral data of two exceptionally luminous gamma-ray outburts observed by the Large Area Telescope (LAT) experiment on board Fermi Gamma-ray Space Telescope from 3C 273 in September 2009. During these…
The blazar 3C 454.3 experienced a major flare in November 2010, making it the brightest $\gamma$-ray source in the sky of the Fermi Large Area Telescope (LAT). We obtain seven daily consecutive spectral-energy distributions (SEDs) of the…
3C 279 showed enhanced flux variations in Fermi-LAT {\gamma}-ray observations from January to June 2018. We present a detailed Fermi-LAT analysis to investigate the variability and spectral behaviors of 3C 279 during the {\gamma}-ray flares…
The well studied blazar 3C 279 underwent a giant $\gamma$-ray outburst in 2014 March-April. The measured $\gamma$-ray flux (1.21 $\pm$ 0.10 $\times$ 10$^{-5}$ ph cm$^{-2}$ s$^{-1}$ in 0.1-300 GeV energy range) is the highest detected from…
The BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra…