112 research outputs found
Discovery of a new INTEGRAL source: IGR J19140+0951
IGR J19140+0951 (formerly known as IGR J19140+098) was discovered with the
INTEGRAL satellite in March 2003. We report the details of the discovery, using
an improved position for the analysis. We have performed a simultaneous study
of the 5-100 keV JEM-X and ISGRI spectra from which we can distinguish two
different states. From the results of our analysis we propose that IGR
J19140+0951 is a persistent Galactic X-ray binary, probably hosting a neutron
star although a black hole cannot be completely ruled out.Comment: 4 pages, 4 figures. Accepted for publication in A&A
Radio Emission from GRO J1655-40 during the 1994 Jet Ejection Episodes
We report multifrequency radio observations of GRO J1655-40 obtained with the
Australia Telescope Compact Array, the Molonglo Observatory Synthesis Telescope
and the Hartebeesthoek Radio Astronomy Observatory at the time of the major
hard X-ray and radio outbursts in 1994 August-September. The radio emission
reached levels of the order of a few Jy and was found to be linearly polarized
by up to 10%, indicating a synchrotron origin. The light curves are in good
agreement with those measured with the VLA, but our closer time sampling has
revealed two new short-lived events and significant deviations from a simple
exponential decay. The polarization data show that the magnetic field is well
ordered and aligned at right angles to the radio jets for most of the
monitoring period. The time evolution of the polarization cannot be explained
solely in terms of a simple synchrotron bubble model, and we invoke a hybrid
`core-lobe' model with a core which contributes both synchrotron and free-free
emission and `lobes' which are classical synchrotron emitters.Comment: 36 pages, 5 tables, 9 figures; accepted for publication in Ap
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