Abstract for Proposal 094481

Legacy Observations of BHXRBs: wind driving mechanism and relation with the jet

Edge-on black hole transients show blue-shifted absorption lines in their X-ray spectra due to hot equatorial disk winds. Blue-shifted absorption lines also been discovered in optical and UV. These features must be produced in an outflow, but the physical conditions required to form them are very different. The three features have never been observed at the same time. It is unclear if they are linked to distinct outflows or simply to different regions. We propose to answer this question with simultaneous time-resolved spectroscopy of a transient BHXRB in X-ray, UV, optical and mid-IR during their hard- intermediate- and soft-states. This will allow us to test if all types of wind features are present simultaneously and whether they display correlated variability among them and with the jet

Details on Observing Strategy and Trigger Criteria
The hard state evolves quickly typically in scales of weeks, in addition to this, the pre-analysis required to determine the safety optimisation of the proposals takes at least one week. Therefore we require mildly disruptive ToO to be executed in a week from the trigger for the first two observations. The soft state can last several months so regular ToO constrains can be applied in the last observation. We will monitor candidate sources with NICER, Swift and optical ground-based telescopes and trigger when XMM and at least optical and one other facilities can obtain useful data to achieve the science gals.