IGR J01054-7253: a new INTEGRAL source discovered in the SMC
ATel #2079; E. Bozzo (ISDC, Geneva, Switzerland) C. Ferrigno (IAAT, Tuebingen, Germany & ISDC, Geneva, Switzerland) M. J Coe (University of Southampton, UK) P. den Hartog (HEPL/KIPAC/Stanford) A. J Bird (University of Southampton, UK), P. Lubinski (ISDC, Geneva, Switzerland) T. J. Maccarone (University of Southampton, UK) V. Beckmann (ISDC, Geneva, Switzerland) P. Ubertini (Iasf-Roma, Italy) K. Watanabe (Florida Gulf Coast University, USA)
on 12 Jun 2009; 09:38 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Nami Mowlavi (Nami.Mowlavi@obs.unige.ch)
Subjects: X-ray, Gamma Ray, Request for Observations, Transient
Referred to by ATel #: 2092
We report on the detection of the new source IGR J01054-7253, with the IBIS/ISGRI detector aboard the INTEGRAL observatory, during the 47 Tucanae and SMC key program observation performed between 2009-06-07 05:26 and 2009-06-11 08:00 UTC (exposure time 124 ks).
The position of the source is Ra: 01:05:27 and Dec: -72:53:33 in the SMC.
Since the detection significance in the 20-40 keV band is 7.3 sigma, the error on this position is 3.5' at 90% confidence level (Gros et al, 2003, A&A 411, L179âL183).
The spectrum of the source, as measured by IBIS/ISGRI, is best fit by using
a simple power law model with photon index 2.5+/-0.9. The flux in the 20-40 keV energy
band is 1.8x10^(-11) ergs/cm^2/s (~3 mCrab). The source is also marginally detected by the JEM-X monitor at a significance of 4 sigma (3-10 keV energy band). The corresponding flux can be estimated in a few mCrab.
We notice that the position of this object is coincident, within the errors,
with the ROSAT source RX J0104.7-7253 (Kahabka P. et al., 1999, A&AS, 136, 81),
whose count rate in the 0.1-2.4 keV band was (1.36+-0.41)x10^(-3).
By assuming a power law spectrum with a photon index of 2 and a Galactic absorption
column density of 5x10^(20) cm^(-2), such a count rate corresponds to an X-ray flux of
Although the IBIS/ISGRI and ROSAT energy bands are very different, this result suggests that either the ROSAT source is not the counter part of IGR J01054-7253, or that this source is
indeed strongly variable.
Swift follow-up observations of this source have already been requested.