Rebrightening of the variable AGILE source in the Cygnus region
ATel #1547; A. Giuliani, P. Caraveo, A. Chen, S. Mereghetti, A. Pellizzoni, S. Vercellone, F. Perotti, F. Fornari, M. Fiorini, A. Zambra (INAF/IASF Milano), 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), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, M. Galli, (INAF/IASF Bologna), 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), P. Cattaneo (INFN Pavia) and P. Giommi, C. Pittori, D. Gasparrini, S. Cutini, B. Preger, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI)
on 27 May 2008; 17:29 UT
Credential Certification: Andrew Chen (chen@iasf-milano.inaf.it)
Subjects: Gamma Ray, >GeV, Transient
While pointing at the Cygnus region, AGILE detected renewed gamma-ray
emission from the transient gamma-ray source previously reported in
ATel #1492, beginning on 2008-05-22 UT.
A preliminary maximum likelihood analysis of the AGILE-GRID (Gamma-Ray
Imaging Detector) data obtained between 2008-05-22 06:00 UT and 2008-05-27
06:00 UT for photon energies above 100 MeV results in a detection
significance of about 6 sigma, with a source flux in excess of 100e-8
ph/cm2/s at energies above 100 MeV. The source positional error box
is centered at Galactic coordinates l = 77.9 deg, b = 2.6 deg, and has a
radius of about 0.5 degrees. We note that the possible counterpart IGR
J20187+4041 = 2MASX J20183871+4041003 (ATel #1497, #1498, #1518) lies
within the 95% source location contour.
A preliminary analysis of the Super-AGILE data over the same time
period and the same sky region does not show any counterpart in the 20-60
keV energy range, with a 3-sigma upper limit of 10 mCrab on the average
flux.
We strongly encourage multi-frequency observations of the field of the
gamma-ray source detected by AGILE in an active gamma-ray flaring state,
including the possible counterpart IGR J20187+4041 = 2MASX J20183871+4041003.