ATel #149; E. Kuulkers (ESA/ESTEC), A. Lutovinov (IKI, Moscow), A. Parmar (ESA/ESTEC), F. Capitanio (IAS, Roma), N. Mowlavi (ISDC), W. Hermsen (SRON, Utrecht)
on 19 Apr 2003; 16:56 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: A.Lutovinov (firstname.lastname@example.org)
Subjects: X-ray, Gamma Ray, Request for Observations, Transient
We report the discovery of a new transient source with the IBIS/ISGRI
detector onboard the INTEGRAL observatory, which we designate as
IGR J17091-3624. The source position is RA=17h09.1m and DEC=-36o24m38s
(equinox J2000, uncertainty ~3').
The source was first seen during a pointed observation between UT 2003
April 14 00:20 and April 15 06:12 with a flux of about 20 mCrab in the
40-100 keV energy band. The source was not evident in
the 15-40 keV band with an upper limit of about 10 mCrab, and shows the
source exhibited a hard spectrum at that time. During subsequent
pointings of the Galactic Center Deep Exposure between UT 2003 April 15
14:25 and April 16 09:06 the source flux had increased to about 40 mCrab
and 25 mCrab in the 15-40 and 40-100 keV band, respectively, showing a
considerable softening of the source spectrum.
The source did not appear in both energy bands in a pointed observation
a week earlier (UT 2003 April 6 15:41 - April 7 14:20), with upper
limits of typically ~10 mCrab.
We encourage follow up observations at various wavelengths.