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New X-ray transient IGR J17473-2721 discovered with INTEGRAL

ATel #467; S. A. Grebenev (IKI, Moscow), S. V. Molkov (IKI, Moscow), R. A. Sunyaev (IKI, Moscow; MPA, Garching)
on 22 Apr 2005; 16:51 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: S.A.Grebenev (sergei@hea.iki.rssi.ru)

Subjects: Radio, Infra-Red, Optical, X-ray, Request for Observations, Black Hole, Neutron Star, Transient

Referred to by ATel #: 500, 521, 634, 1445, 1459, 1461, 1468

We report the discovery with the IBIS/ISGRI telescope on board INTEGRAL of a previously unknown hard X-ray source IGR J17473-2721. The source was detected during ultra deep Open Program observations of the Galactic center field carried out on March 17-28 and April 9-21, 2005. The signal-to-noise ratio for this source at the mosaic image was S/N=16.9 in the 18-45 keV band and S/N=5.6 in the 45-80 keV band. The average flux was equal to 3.87+/-0.23 and 2.8+/-0.5 mCrab in the same bands. The source best-fit position was found to be R.A.=17h47m21s, Decl.=-27d21m29s (equinox 2000.0, uncertainty 2').

The source was also detected during individual revolutions (on a time scale of 3 days) with the S/N ratio ranging from 4-6 in the middle of March to 8-10 in the middle of April. Such behaviour indicates steady brightening of the source with the increase of its 18-45 keV flux from 2.7 to 5.6 mCrab, respectively.

We encourage follow-up observations of this source at all wavelengths.