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IGR17597-2201 and AX1820.5-1434

ATel #155; A. Lutovinov (IKI, Moscow), R. Walter (ISDC), G. Belanger (CEA, Saclay), N. Lund (DSRI), S. Grebenev (IKI, Moscow), C. Winkler (ESA/ESTEC)
on 30 Apr 2003; 09:19 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: A.Lutovinov (aal@hea.iki.rssi.ru)

Subjects: X-ray, Gamma Ray, Request for Observations, Transient, Pulsar

Referred to by ATel #: 156

We report the discovery of a new transient source IGR J17597-2201 with the IBIS/ISGRI detector onboard the INTEGRAL observatory. Its position is RA=17h59.7m and Dec=-22o01m (equinox 2000) with uncertainty ~2'. The source was detected during several deep observations of the Galactic center field. The measured flux in a 15-40 keV energy band was ~5 mCrab (signal to noise ratio S/N ~ 10) during observation on March 30-April 1 and increased to 10-15 mCrab (S/N > 21) during observations on April 15-April 24. At the same time the source was also detected in 40-100 keV energy band at the flux of ~10 mCrab (S/N > 14).

We also report a first detection of hard X-ray emission from a known high mass binary pulsar AX1820.5-1434 on April 19-24 at ~10-15 mCrab in the 15-40 energy band. Previous observations of the same field have not shown the presence of the source in this energy band with an upper limit ~5 mCrab.

We encourage follow up observations at various wavelengths.