INTEGRAL pointed observation of XTEJ1817-330
ATel #742; P. Goldoni (APC & CEA, Saclay), E. Kuulkers (ESA/ESAC, Spain), J. Rodriguez (CEA, Saclay), S. E. Shaw (Southampton, UK/ ISDC Geneva), P. Dubath (ISDC Geneva), J. Chenevez, N. Lund (DNSC, Copenhagen), A. Goldwurm, M. Cadolle Bel (APC & CEA Saclay), M. Del Santo, P. Ubertini, A. Bazzano (INAF/IASF, Rome), C. Winkler (ESA/ESTEC, Netherlands)
on 21 Feb 2006; 17:05 UT
Credential Certification: Paolo Goldoni (firstname.lastname@example.org)
Subjects: X-ray, Gamma Ray, Binary, Black Hole
We report preliminary results of the INTEGRAL ToO observation of the transient
BHC XTEJ1817-330 (ATEL #714, #731) performed from 2006-02-15 01:28:29 (U.T.C.)
to 2006-02-17 11:19:41.0 for a total exposure time of about 200 ksec. The source has
been clearly detected up to 200 keV with no apparent cutoff at flux levels of
about 1 Crab (3-20 keV) and 90 mCrab (20-200 keV).
Preliminary analysis of JEM-X and IBIS/ISGRI data show that the 3-200 keV spectrum
of the source can be well fitted by a disk black body with temperature of 0.9 keV
plus a powerlaw with photon index 2.7.
In agreement with previous reports (ATEL #724, #733, #740), no interstellar
absorption was needed in the fit, suggesting a low column density (Nh~10^21 cm^-2).
The power density spectrum, computed from the 3-15 keV JEM-X light curve,
is consistent with white noise above ~1 mHz, while it is well
represented by a power law with index ~2.07 below 1mHz. We estimate the RMS
fractional amplitude to be ~6% between 0.01mHz and 1mHz.
The relative weakness of the hard component and the low level of variability
suggest that the source has been observed predominantly in the high/soft state,
although some evolution could be seen.
We also searched for signatures of 511 keV emission features in 3 hour-long
sections of the SPI data as well as on the entire observation. No emission was
detected with 3 sigma upper limits respectively of 2.4e-3 ph/cm^2/s and 7.5e-4 ph/cm^2/s.
XTEJ1817-330 will be observed regularly by INTEGRAL in the following
weeks by the Galactic Bulge Monitoring Program (ATEL #734, #738).
Further observations are encouraged to follow the evolution of this source.