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A new hard X-ray source discovered by INTEGRAL: IGR J16442-554

ATEL # 2185; E. Bozzo (ISDC), C.Ferrigno (IAAT/ISDC), J. Chenevez (DTU-NSI), M. Del Santo, A. De Rosa, M. Fiocchi, A. Tarana, P. Ubertini (INAF/IASF-Roma), S. Corbel, D. Goetz, L. Prat, J.-A. Zurita-Heras (CEA-Saclay), M. Renaud (APC/Univ-Paris7), S. Mereghetti, A. Paizis, L. Sidoli (INAF/IASF-Mi), P.R. den Hartog (HEPL/KIPAC/Stanford), L. Kuiper (SRON), I. Negueruela (Universidad de Alicante), S. Piraino (IASF-Pa-INAF), Georg Weidenspointner (MPI), K. Watanabe (FGCU)
on 2 Sep 2009; 17:27 UT
Distributed as an Instant Email Notice (Transients)
Password Certification: Nami Mowlavi (

Subjects: X-ray, Gamma Ray, Transients
Referred to by ATEL #: 2188

During a key program observation of the inner Galactic disc performed between 2009-08-30 14:04 and 2009-09-01 12:03 (UTC), a new source was discovered in the INTEGRAL/IBIS mosaic image.
The best localization is RA: 251.088 DEC: -55.808, with a 90% error radius of 3.6 arcmin.

The source, IGR J16442-5548, is detected with a significance of 7 sigma in the 20-40 keV energy band and of 5 sigma in the 40-100 keV energy band. The corresponding flux is about 7 mCrab. The source is not detected in the JEM-X monitor: upper limits at 3 sigma c.l. are respectively 2 and 5 mCrab in the 3-10 keV and 10-25 keV energy bands. The IBIS/ISGRI spectrum in the 20-100 keV energy range is well described by a power-law with photon index 2.2+/-0.5. The 20-100 keV flux is 1.2e-10 erg/cm^2/s. The light curve exhibits pronounced variability on a few hours time scale.

We did not find any previously known X-ray source in the Simbad database within the INTEGRAL error box. A Swift follow-up is ongoing and multi-wavelength observations are encouraged.

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R. E. Rutledge , Editor
ATEL Mirror v1.0 Updates