We report the first blazar detection by AGILE. AGILE detected 3C 454.3 during a period of strongly enhanced optical emission in 2007 July. AGILE observed the source with a dedicated repointing during the period 2007 July 24-30 with its two co-aligned imagers, the Gamma-Ray Imaging Detector and the hard X-ray imager Super-AGILE sensitive in the 30 MeV to 50 GeV and 18-60 keV ranges, respectively. Over the entire period, AGILE detected gamma-ray emission from 3C 454.3 at a significance level of 13.8 sigma with an average flux (E > 100 MeV) of (280 +/- 40) x 10(-8) photons cm(-2) s(-1). The gamma-ray flux appears to be variable toward the end of the observation. No emission was detected by Super-AGILE in the energy range 20-60 keV, with a 3 sigma upper limit of 2.3 x 10(-3) photons cm(-2) s(-1). The gamma-ray flux level of 3C 454.3 detected by AGILE is the highest ever detected for this quasar and among the most intense gamma-ray sluxes ever detected from flat-spectrum radio quasars.
Agile detection of a strong gamma-ray flare from the blazar 3C 454.3 / S., Vercellone; A. W., Chen; A., Giuliani; A., Bulgarelli; I., Donnarumma; I., Lapshov; M., Tavani; A., Argan; G., Barbiellini; P., Caraveo; V., Cocco; E., Costa; F., D'Ammando; E. D., Monte; G. D., Paris; G. D., Cocco; Y., Evangelista; M., Feroci; M., Fiorini; T., Froysland; F., Fuschino; M., Galli; F., Gianotti; C., Labanti; F., Lazzarotto; P., Lipari; Longo, Francesco; M., Marisaldi; F., Mauri; S., Mereghetti; A., Morselli; L., Pacciani; A., Pellizzoni; F., Perotti; P., Picozza; M., Prest; G., Pucella; M., Rapisarda; P., Soffitta; M., Trifoglio; A., Trois; E., Vallazza; V., Vittorini; A., Zambra; D., Zanello; C., Pittori; F., Verrecchia; D., Gasparrini; S., Cutini; P., Giommi; L. A., Antonelli; S., Colafrancesco; L., Salotti. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 676:(2008), pp. L13-L16.
Agile detection of a strong gamma-ray flare from the blazar 3C 454.3
LONGO, FRANCESCO;
2008-01-01
Abstract
We report the first blazar detection by AGILE. AGILE detected 3C 454.3 during a period of strongly enhanced optical emission in 2007 July. AGILE observed the source with a dedicated repointing during the period 2007 July 24-30 with its two co-aligned imagers, the Gamma-Ray Imaging Detector and the hard X-ray imager Super-AGILE sensitive in the 30 MeV to 50 GeV and 18-60 keV ranges, respectively. Over the entire period, AGILE detected gamma-ray emission from 3C 454.3 at a significance level of 13.8 sigma with an average flux (E > 100 MeV) of (280 +/- 40) x 10(-8) photons cm(-2) s(-1). The gamma-ray flux appears to be variable toward the end of the observation. No emission was detected by Super-AGILE in the energy range 20-60 keV, with a 3 sigma upper limit of 2.3 x 10(-3) photons cm(-2) s(-1). The gamma-ray flux level of 3C 454.3 detected by AGILE is the highest ever detected for this quasar and among the most intense gamma-ray sluxes ever detected from flat-spectrum radio quasars.Pubblicazioni consigliate
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