The soft X-ray component and the hard continuum curvature in black hole binaries

We propose a 40ksec joint XMMNewton/NuSTAR observation of the black hole binarySwift J1753.50127 in its persistent faint low/hard state. This will constrainthe radial stratification of the corona and the spectral curvature of thelow/hard state continuum in the unprecedented 0.770keV band. This will thengive the most unambigious measure of the strength of the soft Xray componentand resolve some of the controversies over the accretion geometry. Theobservation will also help with ongoing calibration/cross calibration effortsfor both satellites. This observation is not time critical, and will be feasiblewhen it best suits the satellites. schedules. An ongoing AMI LA radio monitoringprogramme of Swift J1753.50127 will be adapted to coincide with this XMMNewton/NuSTAR observation. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]