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Swift follow-up of the gigantic TeV outburst of PKS 2155-304 in 2006

L. Foschini·G. Ghisellini·F. Tavecchio·A. Treves·L. Maraschi·M. Gliozzi·C. M. Raiteri·M. Villata·E. Pian·G. Tagliaferri·G. Tosti·R. M. Sambruna·G. Malaguti·G. Di Cocco·P. Giommi
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Abstract

At the end of July 2006, the blazar PKS 2155-304 (z=0.116) underwent a strong outburst observed at TeV energies by HESS (up to 17 Crab flux level at E > 200 GeV). The Swift satellite followed the evolution of the source for about one month. The data analysis - reported in another paper - has shown that, despite the violent activity at TeV energies, the synchrotron energy distribution increased in normalization, but only with a small shift in frequency. In the present work, we fit the broad-band spectrum with a log-parabolic model, to search for indications of intrinsic curvature, which in turn is usually interpreted as a signature of energy-dependent acceleration mechanisms of electrons.

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L. Foschini, G. Ghisellini, F. Tavecchio, A. Treves, L. Maraschi, M. Gliozzi, C. M. Raiteri, M. Villata, E. Pian, G. Tagliaferri, G. Tosti, R. M. Sambruna, G. Malaguti, G. Di Cocco, P. Giommi. 2007-03-30. Swift follow-up of the gigantic TeV outburst of PKS 2155-304 in 2006. https://doi.org/10.1063/1.2757336

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