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ATEL # 2983; E. Bozzo (ISDC, University of Geneva), J. Rodriguez (CEA, Saclay), J. Wilms (Dr. Karl Remeis-Observatory), C. Ferrigno (ISDC, University of Geneva), S. Mereghetti (IASF/INAF, Milano), J. Tomsick (SSL, Berkeley), D. Gotz, I. Caballero, L. Prat (CEA, Saclay), P. Ubertini, M. Fiocchi, A. Tarana (IASF/INAF Roma), D. Klochkov (IAAT), K. Watanabe (FGCU), V. Sguera (INAF/IASF, Bologna), G. Skinner (CRESST/GSFC/UMCP), I. Kreykenbohm (Dr. Karl Remeis-Observatory), R. Terrier (CNRS/APC).
on 29 Oct 2010; 17:08 UT
Distributed as an Instant Email Notice (Transients)
Password Certification: E. Bozzo (email@example.com)
Subjects: Binaries, Neutron Stars, Transients
Referred to by ATEL #: 2985
During the INTEGRAL observations of GRS1915+105, performed from 2010 October 28 at 18:25 to 2010 October 29 at 00:10 UTC (total exposure time ~20 ks), IBIS/ISGRI detected a renewed activity from the transient binary system IGR J19294+1816. The nature of the source is still debated, and it is classified as a possible Be binary system or supergiant fast X-ray transient (SFXT, Rodriguez et al. 2009, A&A, 508, 889).
During the latest INTEGRAL observations, the source is detected in the IBIS/ISGRI mosaic at a significance level of 30 sigma (20-40 keV). Its spectrum is best fit with a blackbody model of kT=4.8+/-0.4 keV (effective exposure time 13 ks). The estimated flux in the 20-40 keV energy band is (4.9+/-0.3)E-10 erg/cm^2/s (uncertainties at 90% c.l.).
The source was outside the JEM-X FOV during the entire observational period.
Previous INTEGRAL observations in the direction of IGR J19294+1816 were performed from 2010 October 22 at 23:04 to 2010 October 23 at 05:31, for a total exposure time of 20 ks. In that occasion IGR J19294+1816 was not detected in the IBIS/ISGRI FOV and we estimated a 3 sigma c.l. upper limit on the hard X-ray flux from the source of 5.6 mCrab, corresponding to ~4.3E-11 erg/cm^2/s.
We encourage observations at other wavelengths to characterize the nature of this interesting transient source.