SuperAGILE detection of a type I X-ray burst from a position consistent with HETE J1900.1-2455
ATel #2238; Y. Evangelista, E. Del Monte, M. Feroci, L. Pacciani, E. Costa, I. Donnarumma, I. Lapshov, F. Lazzarotto, M. Rapisarda, P. Soffitta, A. Argan, A. Trois , M. Tavani, G. Piano, G. Pucella, F. D'Ammando, S. Sabatini, E. Striani, V. Vittorini (INAF/IASF Roma), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, M. Galli (INAF/IASF Bologna), A. Chen, A. Giuliani, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milano), A. Pellizzoni, M. Pilia (OAC/INAF Cagliari), S. Vercellone (INAF/IASF Palermo), G. Barbiellini, F. Longo, E. Moretti, E. Vallazza (INFN Trieste), P. Picozza, A. Morselli (INFN Roma-2), M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), A. Rappoldi (INFN Pavia) and C. Pittori, F. Verrecchia, P. Santolamazza, P. Giommi (ASDC) and L. Salotti (ASI)
on 9 Oct 2009; 22:05 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Marco Feroci (marco.feroci@iasf-roma.inaf.it)
Subjects: X-ray, Request for Observations, Binary, Neutron Star, Transient
On 9 October 2009 02:57:43 UT SuperAGILE detected a type I
X-ray burst from a sky position consistent with the accreting
millisecond pulsar HETE J1900.1-2455. The burst was significantly
detected only at energies below 28 keV, as typical of type I
X-ray bursts in SuperAGILE, due to their soft energy spectrum.
The burst profile is double-peaked, with a total duration of
about 13 s, similar to previous bursts from this source (e.g.,
Suzuki et al. PASJ 2007 or Falanga et al. A&A 2008). Using the
data in the energy range 17-25 keV, we measure an average burst
flux of 1.3e-8 erg/cm2/s (under the assumption of a Crab-like
energy spectrum). The latest notified X-ray burst from this
source was on April 2009 (Watts et al., ATel #2004).
The persistent emission from HETE J1900.1-2455 is currently
detected by SuperAGILE at an average flux level of about
50 mCrab (20-60 keV), on daily integrations.
The source localization by SuperAGILE is composed by two
one-dimensional projections. One of the two projections of the
detected burst position is unambiguously consistent with the
position of HETE J1900.1-2455. The other 1D image shows a potential
ambiguity due to a secondary peak, possibly due to a statistical
fluctuation. In the hypothesis of a source identification with this
secondary peak, the burst localization would be
(RA,Dec) =(294.3635, -23.7796), with an error radius of 6 arcmin.
This position corresponds to Galactic coordinates
(l,b)=(15.845,-20.260) and it has no known source counterpart yet.
We however consider the association with HETE J1900.1-2455 more likely.
