Disk-Jet Connection in Black Hole Sources
| Autor: | Mayur Shende, Prasad Subramanian |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Astrophysics::High Energy Astrophysical Phenomena
galaxies: active – galaxies: jets – magnetohydrodynamics (MHD) – Sun: coronal mass ejections (CMEs) accretion accretion discs – galaxies: active Astrophysics::Solar and Stellar Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics::Earth and Planetary Astrophysics Astrophysics::Galaxy Astrophysics |
| DOI: | 10.5281/zenodo.5516631 |
| Popis: | Several active galactic nuclei and microquasars exhibit interesting observational behavior in which significant dips in the X-ray light curve are followed by ejections of plasmoids at radio frequency that move at relativistic speeds. We envisage the plasmoids as pre-existing current carrying magnetic flux ropes that were initially anchored in the accretion disk-corona. The plasmoids are ejected outwards via a mechanism called the toroidal instability (TI). The TI, which was originally explored in the context of laboratory tokamak plasmas, has been very successful in explaining coronal mass ejections from the Sun. Our detailed model predictions compare favorably with a representative set of multi-epoch observations of radio emitting knots from the radio galaxy 3C 120. On the other hand, the temporal behaviour of X-rays is thought to arise from the rapid collapse of the hot, inner parts of their accretion disks. The collapse can occur over the radial infall time-scale of the inner accretion disk. However, estimates of this time-scale are hindered by a lack of knowledge of the operative viscosity in the collisionless plasma comprising the inner disk. We use published simulation results for cosmic ray diffusion through turbulent magnetic fields to arrive at a viscosity prescription appropriate to hot accretion disks. We construct simplified disk models using this viscosity prescription and estimate disk collapse time scales for 3C 120, 3C 111, and GRS 1915+105. The Shakura–Sunyaev α parameter resulting from our model ranges from 0.02 to 0.08. Our inner disk collapse time-scale estimates agree well with those of the observed X-ray dips. We find that the collapse time-scale is most sensitive to the outer radius of the hot accretion disk. Combining, our work outlines a plausible scenario for episodes of (inner) disk collapse accompanied by blob ejection. |
| Databáze: | OpenAIRE |
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