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标题：AGILE detection of a strong gamma ray flare from the blazar S5 0716 714 during September-October 2007
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作者：F. D'Ammando ; A.W. Chen ; M. Villata 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2008
卷号：2008
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report the g -ray activity from the Intermediate BL Lac S5 0716+714 during 2007 September– October observations by the AGILE satellite, coincident with a period of intense optical activity of the source monitored by GASP–WEBT. AGILE observed the source with its two co-aligned imagers, the Gamma-Ray Imaging Detector (GRID) and the hard X-ray imager (Super-AGILE) sensitive in the energy range 30MeV–50 GeV and 18–60 keV respectively, in two different periods: the first between 4 and 23 September 2007, the second between 24 October and 1 November 2007. Over the period 7–12 September, AGILE detected g -ray emission from the source at a significance level of 9.6-s with an average flux (E>100MeV) of (97±15)×10−8 photons cm−2 s−1, increasing by a factor of at least four within three days. No emission was detected by Super-AGILE in the energy range 18–60 keV, with a 3-s upper limit of 10 mCrab in 335 ksec. The g -ray flux of S5 0716+714 detected by AGILE is the highest ever detected for this blazar and one of the most intense g -ray fluxes detected from a BL Lac object. The Spectral Energy Distribution (SED) of mid-September seems to be consistent with the synchrotron self-Compton (SSC) emission model, but only by including two SSC components with different variability. In October 2007 AGILE repointed toward S5 0716+714 following an intense optical flare, measuring an average flux of (47±11)×10−8 photons cm−2 s−1 at a significance level of 6.0-s . The g -ray flux during both AGILE pointings appears to be highly variable on timescales of 1 day.