http://arxiv.org/abs/2204.08802
Black hole accretion discs can produce powerful outflowing plasma (disc winds), seen as blue-shifted absorption lines in stellar and supermassive systems. These winds in Quasars have an essential role in controlling galaxy formation across cosmic time, but there is no consensus on how these are physically launched. A single unique observation of a stellar-mass black hole GRO J1655-40 showed the high wind density estimated from an absorption line from the metastable level of Fe xxii and ruled out X-ray heating (thermal-radiative wind) for the low observed luminosity. This left magnetic driving as the only viable mechanism, motivating unified models of magnetic winds in both binaries and Quasars. Here we reanalyse these data using a photoionisation code that includes the contribution of radiative cascades and collisions in populating the metastable level. The effect of radiative cascades reduces the inferred wind density by orders of magnitude. The derived column is also optically thick, so the source is intrinsically more luminous than observed. We show that a thermal-radiative wind model calculated from a radiation hydrodynamic simulation matches well with the data. We revisit the previous magnetic wind solution and show that this is also optically thick. Hence, it requires a larger source luminosity, and it struggles to reproduce the overall ion population at the required density (both new and old). These results remove the requirement for a magnetic wind in these data and remove the basis of the self-similar unified magnetic wind models extrapolated to Quasar outflows.
R. Tomaru, C. Done and J. Mao
Wed, 20 Apr 22
36/62
Comments: 10 pages, 10 figures, submitted to MNRAS
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