Abstract for Proposal 087199
Studying Black Hole Binaries during their outburst from radio to X-rays
During their outbursts Black Holes Binaries (BHB) can pass through two main
spectral states defined by the shape of their X-rays spectra, the hard state and
the soft state. The simple assumption is that the spectral and temporal changes
are due to modification of the mass accretion rate, but the picture is more
complex and another parameter is required to explain behavior of these objects.
In order to understand connections between jets and the accretion flow and the
nature of physicals processes that occur in BHB, we propose two simultaneous ToO
observations with INTEGRAL and XMM, one for each spectral states.
Details on Observing Strategy and Trigger Criteria
A source with a photon index less than 2 and a flux higher than 100 mCrab in
the IBIS 30-50 keV band, Swift/BAT 15-50 keV band or in the MAX/GSC 2-20 keV
band will be our trigger criteria for the first observation in the hard state.
The second observation will be triggered once the source passed in HSS
determined by a) an Atel, b) a significant softening of the photon index in the
spectral shape (Γ > 2.5), c) a significant variation of the hardness ratio
(≃ 25% change between the 3–12 and 30–80 keV bands, i.e., in JEM-X/XRT or
ISGRI/BAT). The two XMM observations of 10 ks each will be distributed
simultaneously on each INTEGRAL observation.