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INTEGRAL discovers the new hard X-ray source IGR J19294+1816

ATel #1997; M. Turler (ISDC, Versoix, Switzerland), J. Rodriguez (CEA, Saclay, France), C. Ferrigno (ISDC, Versoix, Switzerland), on behalf of a larger collaboration
on 31 Mar 2009; 08:31 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Jerome Rodriguez (jrodriguez@cea.fr)

Subjects: Request for Observations, AGN, Binary, Black Hole, Cataclysmic Variable, Neutron Star, Transient, Pulsar

Referred to by ATel #: 1998, 1999, 2002, 2008, 4135

A new hard X-ray source has been detected by the IBIS/ISGRI camera on the INTEGRAL gamma-ray observatory during an observation of the field around GRS 1915+105 taken on 2009-03-27 from 11:56 UT to 17:43 UT. The source, named IGR J19294+1816, is located at R.A.=292.42 deg and Dec=+18.28 deg (equinox J2000) with an uncertainty on the position of about 3 arcmin (68% confidence).

It is well detected (8.3 sigma) in the overall IBIS/ISGRI mosaic image in the 20-40 keV band with a flux of about 14 +/- 2 mCrab. The source is not detected in the image at higher energies (40-80 keV) and we lack information at lower energies as the source is just outside the area simultaneously covered by the JEM-X instrument.

The time-averaged spectrum of the source is consistent with a single powerlaw in the 18-50 keV range with a rather steep photon index of Gamma = 4.0 +/-0.7. The model flux in the 20-40 keV band is of 1.1 E-10 erg/cm^2/s.

Within the observation, there is no evidence for significant time variability, but the source was not detected in either of the two previous INTEGRAL observations of the same field taken on 2009-03-18 (10:39 to 16:45 UT) and on 2009-03-21 (10:28 to 16:15 UT) with a 3-sigma upper limit of about 6 mCrab (20-40 keV).

We note the presence of the Einstein source 2E 1927.5+1805 about 5 arcmin away from the obtained position at (RA,Dec) = (292.44,+18.20) (J2000) (with an uncertainty of about 1 arcmin, SIMBAD, McDowell 1994). Given the positional uncertainties of the 2 sources, we do not exclude an association of IGR J19294+1816 and 2E 1927.5+1805.

Follow-up observations are encouraged in order to check this possible association, and determine the type of this new hard X-ray transient.