Magnetic origin of black hole winds across the mass scale

Invariably, black hole accretion disks seem to produce plasma outflows that result in blue-shifted absorption features in their spectra(1). The X-ray absorption-line properties of these outflows are diverse, ranging in velocity from non-relativistic(2) (-300 km s(-1)) to sub-relativistic(3) (-0.1c, where c is the speed of light) and a similarly broad range in the ionization states of the wind plasma(2,4). We report here that semi-analytical, self-similar magnetohydrodynamic wind models that have successfully accounted for the X-ray absorber properties of supermassive black holes(5,6) also offer a good fit to the highresolution X-ray spectrum of the accreting stellar-mass black hole GRO J1655-40. This provides an explicit theoretical argument of their magnetohydrodynamic origin (aligned with earlier observational claims)(7) and supports the notion of a universal magnetic structure of the observed winds across all known black hole sizes.