UCL Discovery

Abstract

(and Motivation] State transitions in X-ray binaries are manifestations of instabilities in the accretion in/outflow. Therefore, time dependence in the energetics must to be taken into account to understand such transitions. However, most spectral models assume a static, steady-state scenario, and therefore work well only when the source is either in the hard state or in the soft state. For example, a compact jet model, coupled with a T similar to R-3/4 accretion disk and a thermal blackbody (see e.g. (Markoff et al. 2005) for a description of the model), has been successfully used to model broadband spectra of several X-ray binaries in the hard state, but not the intermediate states. With the long-term goal to study time dependence, we present new results of studying quasi-simultaneous broadband data from radio to X-rays for GX 339-4 and J1118+480 in the hard X-ray state, using the jet model, to constrain system geometry and emission processes, which will in turn serve as starting points for the time-dependent models.