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IGR J00234+6141: A new weak hard X-ray source found by INTEGRAL

ATel #394; P. R. den Hartog (1), L. Kuiper (1), W. Hermsen (1, 2), J. Vink(1), J. J.M. in 't Zand (1, 3), R. H.D. Corbet (4), R. Remillard (5) (1 SRON Utrecht; 2 University of Amsterdam; 3 University of Utrecht; 4 NASA/GSFC and USRA; 5 MIT)
on 19 Jan 2005; 09:45 UT
Credential Certification: P.R. den Hartog (Hartog@sron.nl)

Subjects: X-ray, Gamma Ray, Binary, Neutron Star

Referred to by ATel #: 709

We report the discovery by INTEGRAL of a new hard X-ray source, IGR J00234+6141. This source was detected accumulating data from different observations in December 2003 and February 2004 resulting in a 1.6-Ms exposure targeting the Cassiopeia region. The source is weak with a flux of 1.20 +/- 0.15 mCrab and a detection significance of 8 sigma in the energy band 20-30 keV of IBIS/ISGRI. Also in the 30-40 keV band the source is seen, at a 3.8-sigma level with flux 0.8 +/- 0.2 mCrab. Corresponding photon fluxes are (1.35 +/- 0.17)E-5 ph/cm2/s/keV and (4.25 +/- 1.13)E-6 ph/cm2/s/keV. The source is too weak to perform variability studies using the presently available INTEGRAL data.

The best source postion is R.A. = 0h 23m 24s, Decl. = +61o 41' 32" (J2000) with an estimated 3' accuracy (90% confidence level). The position of the ROSAT X-ray source 1RXS J002258.3+614111, which is located 3.15' from the INTEGRAL centroid, is marginally consistent with the INTEGRAL position. A newly derived RXTE-ASM light curve shows a marginal detection of the source, and no modulation was found.

Given its position close to the Galactic plane (b = -1 deg.), the lack of a radio counterpart and the nature of the majority of previously reported new INTEGRAL sources, it is likely to be an X-ray binary, rather than a source with an extragalactic origin.