The Bright γ-ray Flare of 3C 279 in 2015 June: AGILE Detection and Multifrequency Follow-up Observations
C. Pittori ; F. Lucarelli ; F. Verrecchia ; C. M. Raiteri, M. Villata, V. Vittorini, M. Tavani, S. Puccetti, M. Perri, I. Donnarumma , S. Vercellone, J. A. Acosta-Pulido, R. Bachev, E. Benitez, G. A. Borman, M. I. Carnerero, D. Carosati, W. P. Chen, Sh. A. Ehgamberdiev, A. Goded, T. S. Grishina, D. Hiriart, H. Y. Hsiao, S. G. Jorstad, G. N. Kimeridze, E. N. Kopatskaya, O. M. Kurtanidze, S. O. Kurtanidze, V. M. Larionov, L. V. Larionova, A. P. Marscher, D. O. Mirzaqulov, D. A. Morozova, K. Nilsson, M. R. Samal, L. A. Sigua, B. Spassov, A. Strigachev, L.O. Takalo, L. A. Antonelli, A. Bulgarelli, P. Cattaneo, S. Colafrancesco, P. Giommi, F. Longo, A. Morselli, F. Paoletti
Mar - 2018
DOI: 10.3847/1538-4357/aab1f9

journal : The Astrophysical Journal

Volume : 856 ; Issue : 2
type: Article Journal

We report the AGILE detection and the results of the multifrequency follow-up observations of a bright γ-ray flare of the blazar 3C 279 in 2015 June. We use AGILE and Fermi gamma-ray data, together with Swift X-ray andoptical-ultraviolet data, and ground-based GASP-WEBT optical observations, including polarization information, to study the source variability and the overall spectral energy distribution during the γ-ray flare. The γ-ray flaring data, compared with as yet unpublished simultaneous optical data that will allow constraints on the big blue bump disk luminosity, show very high Compton dominance values of ~100, with the ratio of γ-ray to optical emission rising by a factor of three in a few hours. The multiwavelength behavior of the source during the flare challenges one-zone leptonic theoretical models. The new observations during the 2015 June flare are also compared with already published data and nonsimultaneous historical 3C 279 archival data.

keywords : galaxies: active; gamma rays: galaxies; polarization; quasars: individual (3C 279) ; radiation mechanisms: non-thermal; X-rays: general