AGILE detection of a gamma-ray source possibly associated with Blazar TXS 0716+714

ATel #1221; A. Giuliani, S. Vercellone, A. Chen, S. Mereghetti, A. Pellizzoni, F. Perotti, F. Fornari, M. Fiorini, P. Caraveo, A. Zambra (INAF/IASF Milano), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, V. Vittorini, E. Costa, M. Feroci, I. Donnarumma, L. Pacciani, E. Del Monte, F. Lazzarotto, P. Soffitta, Y. Evangelista, I. Lapshov, M. Rapisarda, A. Argan, A. Trois , G. De Paris (INAF/IASF Roma), G. Barbiellini, F. Longo (INFN Trieste), P. Picozza, A. Morselli (INFN Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), F. Mauri (INFN Pavia) and P. Giommi, C. Pittori, L. A. Antonelli, D. Gasparrini, S. Cutini, F. Verrecchia (ASDC) and L. Salotti (ASI)
on 21 Sep 2007; 15:53 UT
Credential Certification: Stefano Vercellone (stefano@iasf-milano.inaf.it)

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The AGILE satellite, currently in its science performance verification phase, during the Observing Block that started on 2007-09-04 12:00 UT, detected significant gamma-ray emission from a source possibly associated with blazar TXS 0716+714.

A preliminary maximum likelihood analysis of the AGILE-GRID (Gamma-Ray Imaging Detector) data obtained between 2007-09-10 13:50 UT and 2007-09-20 10:13 UT for photon energies above 100 MeV results in a detection significance of about 8 sigma. The positional error box, that does not yet take into account possible systematic effects, is centered at Galactic coordinates l = 143.8 deg, b = 27.6 deg. The 95% confidence level contour has a radius of about 0.4 degrees. The blazar TXS 0716+714, that has been associated with the gamma-ray source 3EG J0721+7120, lies at a distance of 0.44 degrees from the best fit position of the gamma-ray source. We therefore tentatively associate the AGILE source with this blazar.

Considering that the in-flight calibration of the GRID is still ongoing, and despite the preliminary GRID positioning capability at off-axis angles (20 to 40 deg for this observation), we strongly encourage multi-frequency observations of the field of the gamma-ray source detected by AGILE. The AGILE pointing of the Galactic plane region that includes this gamma-ray source will continue until 2007-09-23 12:00 UT.