Fast multi-wavelength broad-band and QPO variability in a black hole X-ray binary: accretion flow and/or a jet origin?

Fast variability in X-ray binaries has been studied for many decades, which is associated with accretion flows (in X-rays) and recently confirmed from jets (at least in the infra-red band). I will present results of observations of a black hole X-ray binary in hard state with simultaneous coverage in X-ray, optical and infra-red bands. A Quasi Periodic Oscillation (QPO) is detected for the first time in infra-red. Interestingly, the QPO is also detected in optical and the frequency in both these bands is half the frequency of the QPO in X-rays (classified as type-C) in the broad 0.3-60 keV range. The infra-red power spectrum also exhibits broad-band noise similar to the X-ray power spectrum and is correlated. Hence, we see strong correlated variability in the emission from the accretion disk, corona/hot flow and the jet. With the known origin of X-ray variability in accretion flows, I will discuss if this can manifest itself in jets providing a mechanism for jet variability in the framework of existing models (e.g., Ingram & Done 2011, Veledina et al. 2013, Drappeau et al. 2015). This will provide strong constraints on the structure and geometry of these systems and insight into their disk-jet coupling.