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IGR J17329-2731: a new X-ray transient discovered by INTEGRAL

ATel #10644; A. Postel (ISDC, Switzerland), E. Kuulkers (ESA/ESTEC, Netherlands), V. Savchenko (ISDC, Switzerland), C. Sanchez-Fernandez (ESA/ESAC, Spain), R. Wijnands (UVA, Netherlands), K. Pottschmidt (NASA-GSFC/UMBC, USA), V. Beckmann (CNRS/IN2P3, France), E. Bozzo (ISDC, Switzerland)
on 15 Aug 2017; 21:27 UT
Distributed as an Instant Email Notice Transients
Credential Certification: E. Bozzo (enrico.bozzo@unige.ch)

Subjects: X-ray, Transient

Referred to by ATel #: 10645, 10653, 10682, 10685, 11273

During our monitoring INTEGRAL observations performed in the direction of the Galactic Bulge (see ATel #438), a new X-ray transient was detected in the IBIS/ISGRI mosaic with a best determined position of RA, Dec (J2000.0) = 263.2274 deg, -27.5307 deg (the associated 90% confidence level uncertainty is 2.5 arcmin). We designate the source as IGR J17329-2731.

The source displayed a strong flare during pointing #35 in satellite revolution 1850 (on 2017 August 13 from 16:35 to 17:05 UTC). The detection significance reached 10.5 sigma in the IBIS/ISGRI 20-40 keV energy band. The source was not detected in the 40-80 keV energy range. The estimated 20-40 keV flux from the mosaic was of 56+/-5 mCrab. The source was at the rim of the JEM-X field-of-view during this pointing, and not detected.

IGR J17329-2731 is only marginally detected when all the other IBIS/ISGRI data collected in the direction of the source during the satellite revolutions 1849 and 1850 (from 2017 August 10 at 11:25 to August 13 at 18:41 UTC) are summed together (excluding pointing #35 in revolution 1850). In this case the source is detected at 6.6 sigma in the 20-40 keV energy band, with a roughly estimated corresponding X-ray flux of 8.8+/-1.3 mCrab. The source was not detected in the corresponding JEM-X mosaic and we estimated a 3 sigma upper limit of 6 mCrab in the 3-10 keV energy band.

Follow-up observations of the source are encouraged. Additional INTEGRAL observations in the direction of IGR J17329-2731 are planned for August 21.