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ATEL # 2772; M. Tavani (INAF-IASF-Rm and Univ. Tor Vergata), F. Lucarelli, C. Pittori, F. Verrecchia (ASDC), A. Bulgarelli, F. Gianotti, M. Trifoglio (INAF/IASF Bologna), E. Striani (Univ. Tor Vergata), S. Sabatini, G. Piano (INAF/IASF Roma), A. Argan, A. Trois, G. De Paris, V. Vittorini, E. Costa, I.Donnarumma, M. Feroci, L. Pacciani, E. Del Monte, F. Lazzarotto, P. Soffitta, Y. Evangelista, I. Lapshov (INAF-IASF-Rm), A. Chen, A. Giuliani (INAF-IASF-Milano), M. Marisaldi, G. Di Cocco, C. Labanti, F. Fuschino, M. Galli (INAF/IASF Bologna), P. Caraveo, S. Mereghetti, F. Perotti (INAF/IASF Milano), G. Pucella, M. Rapisarda (ENEA-Roma), A. Pellizzoni, M. Pilia (INAF/OA-Cagliari), G. Barbiellini, F. Longo (INFN Trieste), P. Picozza, A. Morselli (INFN and Univ. Tor Vergata), M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), S. Vercellone, F.D'Ammando (INAF/IASF-Palermo), P.W. Cattaneo, A. Rappoldi (INFN Pavia), P. Giommi, P. Santolamazza (ASDC), S. Colafrancesco and L. Salotti (ASI)
on 5 Aug 2010; 13:04 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Carlotta Pittori (email@example.com)
Subjects: Gamma Ray, >GeV, Request for Observations, Binaries, Pulsars, Transients
Referred to by ATEL #: 2780, 2782
AGILE is detecting transient gamma-ray emission above 100 MeV from a source near the Galactic plane and positionally consistent with the binary pulsar PSR B1259-63 (J2000 coordinates: RA: 13 02 47.66, Dec: -63 50 08.6; l = 304.1836, b = -0.9916).
Integrating from 2010-08-02 06:40 UT to 2010-08-04 04:00 UT, a preliminary maximum likelihood analysis yields a detection centered at Galactic coordinates (l,b) = (304.7,-0.8) ± 0.6 (stat.) ± 0.1 (syst.) (RA=196.9,Dec=-63.7 J2000), with a significance level of about 4.5 sigma, and a gamma-ray flux above 2 x 10E-6 ph/cm2/sec for photon energies above 100 MeV. An independent analysis based on the false discovery rate (FDR) method gives a probability of less than 0.001 for the signal to be consistent with the null hypothesis.
We note that this transient gamma-ray source is positionally consistent with the pulsar binary system PSR B1259-63 made of a 49.96 sec radio pulsar orbiting around a Be star companion in a highly elliptical orbit (of period P = 3.38 yrs). The pulsar is now in the approaching-to-periastron part of the orbit, and is expected to reach the region close to periastron in mid-December 2010. Time variable high-energy emission (ATel #249, M. Beilicke et al.) can be produced by the interaction of the relativistic pulsar wind with the gaseous outflow from the Be star companion (e.g., Tavani & Arons, 1997, ApJ, 499, 439).
Multifrequency observations of the PSR B1259-63 region are strongly encouraged as well as monitoring of the binary pulsar system.