AGILE detection of variable γ-ray activity from the blazar S5 0716+714 in September-October 2007

被引：34

作者：

Chen, A. W. ^{[1
,2
]}

D'Ammando, F. ^{[3
,4
]}

Villata, M. ^{[5
]}

Raiteri, C. M. ^{[5
]}

Tavani, M. ^{[3
,4
]}

Vittorini, V. ^{[2
,3
]}

Bulgarelli, A. ^{[6
]}

Donnarumma, I. ^{[3
]}

Ferrari, A. ^{[5
,7
]}

Giuliani, A. ^{[1
]}

Longo, F. ^{[8
,9
]}

Pacciani, L. ^{[3
]}

Pucella, G. ^{[3
]}

Vercellone, S. ^{[1
]}

Argan, A. ^{[3
]}

Barbiellini, G. ^{[8
,9
]}

Boffelli, F. ^{[10
]}

Caraveo, P. ^{[1
]}

Carosati, D. ^{[11
]}

Cattaneo, P. W. ^{[10
]}

Cocco, V. ^{[3
]}

Costa, E. ^{[3
]}

Del Monte, E. ^{[3
]}

De Paris, G. ^{[3
]}

Di Cocco, G. ^{[6
]}

Evangelista, Y. ^{[3
]}

Feroci, M. ^{[3
]}

Fiorini, M. ^{[1
]}

Froysland, T. ^{[2
,4
]}

Frutti, M. ^{[3
]}

Fuschino, F. ^{[6
]}

Galli, M. ^{[12
]}

Gianotti, F. ^{[6
]}

Kurtanidze, O. M. ^{[13
,14
]}

Labanti, C. ^{[6
]}

Lapshov, I. ^{[3
]}

Larionov, V. M. ^{[15
]}

Lazzarotto, F. ^{[3
]}

Lipari, P. ^{[16
]}

Marisaldi, M. ^{[6
]}

Mastropietro, M. ^{[17
]}

Mereghetti, S. ^{[1
]}

Morelli, E. ^{[6
]}

Morselli, A. ^{[18
]}

Pasanen, M. ^{[19
]}

Pellizzoni, A. ^{[1
]}

Perotti, F. ^{[1
]}

Picozza, P. ^{[18
]}

Porrovecchio, G. ^{[3
]}

Prest, M. ^{[20
]}

机构：

[1] INAF IASF Milano, I-20133 Milan, Italy

[2] CIFS Torino, I-10133 Turin, Italy

[3] INAF IASF Roma, I-00133 Rome, Italy

[4] Univ Roma Tor Vergata, Dip Fis, I-00133 Rome, Italy

[5] Osserv Astron Torino, INAF, Turin, Italy

[6] INAF IASF Bologna, I-40129 Bologna, Italy

[7] Univ Turin, Dip Fis Gen, I-10125 Turin, Italy

[8] Ist Nazl Fis Nucl, I-34127 Trieste, Italy

[9] Dip Fis, I-34127 Trieste, Italy

[10] Ist Nazl Fis Nucl, I-27100 Pavia, Italy

[11] Armenzano Astron Observ, Assisi, Italy

[12] ENEA, I-40129 Bologna, Italy

[13] Astrophys Inst Potsdam, Potsdam, Germany

[14] Landessternwarte Heidelberg Konigstuhl, Heidelberg, Germany

[15] St Petersburg State Univ, Astron Inst, St Petersburg, Russia

[16] Ist Nazl Fis Nucl Roma La Sapienza, I-00185 Rome, Italy

[17] CNR, Ist Metodol Inorgan Plasmi, Area Ricerca Montelibretti Roma, I-00185 Rome, Italy

[18] Ist Nazl Fis Nucl Roma Tor Vergata, I-00133 Rome, Italy

[19] Univ Turku, Tuorla Observ, SF-20500 Turku, Finland

[20] Univ Insubria, Dip Fis, I-22100 Como, Italy

[21] ENEA, I-00044 Frascati, Roma, Italy

[22] ASI ASDC, I-00044 Frascati, Roma, Italy

[23] ASI, I-00198 Rome, Italy

来源：

ASTRONOMY & ASTROPHYSICS | 2008年 / 489卷 / 03期

关键词：

gamma rays : observations; galaxies : BL Lacertae objects : general; galaxies : BL Lacertae objects : individual : S5 0716+714;

D O I：

10.1051/0004-6361:200810553

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Aims. We report the gamma-ray activity from the intermediate BL Lac S5 0716+714 during observations acquired by the AGILE satellite in September and October 2007. These detections of activity were contemporaneous with a period of intense optical activity, which was monitored by GASP-WEBT. This simultaneous optical and gamma-ray coverage allows us to study in detail the light curves, time lags, gamma-ray photon spectrum, and Spectral Energy Distributions (SEDs) during different states of activity. Methods. AGILE observed the source with its two co-aligned imagers, the Gamma-Ray Imaging Detector ( GRID) and the hard X-ray imager (Super-AGILE), which are sensitive to the 30 MeV-50 GeV and 18-60 keV energy ranges, respectively. Observations were completed in two different periods, the first between 2007 September 4-23, and the second between 2007 October 24-November 1. Results. Over the period 2007 September 7-12, AGILE detected gamma-ray emission from the source at a significance level of 9.6-sigma with an average flux (E > 100 MeV) of ( 97 +/- 15) x 10(-8) photons cm(-2) s(-1), which increased by a factor of at least four within three days. No emission was detected by Super-AGILE for the energy range 18-60 keV to a 3-sigma upper limit of 10 mCrab in 335 ks. In October 2007, AGILE repointed toward S5 0716+714 following an intense optical flare, measuring an average flux of (47 +/- 11) x 10(-8) photons cm(-2) s(-1) at a significance level of 6.0-sigma. Conclusions. The gamma-ray flux of S5 0716+714 detected by AGILE is the highest ever detected for this blazar and one of the most intense gamma-ray fluxes detected from a BL Lac object. The SED of mid-September appears to be consistent with the synchrotron self-Compton (SSC) emission model, but only by including two SSC components of different variabilities.

引用

页码：L37 / U7

页数：5

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