Global numerical simulations of accretion flow in the vicinity of Black Hole by Bhupendra Mishra (LANL)

  • ustav
  • 13.05.2021
One of the greatest recent discoveries in astronomy was imaging the first black hole (M87) using the Event Horizon Telescope (EHT). After this discovery by EHT, we are fairly confident that all the numerical speculations done using global general relativistic magnetohydrodynamical (GRMHD) simulations are playing a key role in modeling accretion flows very close to the black hole.

Whenever an unfortunate star gets too close to a black hole, it starts to accrete into the black hole. The accreting star also carries its own little magnetic field with it. Now what happens to this magnetic field? Does it play a key role in shaping the accretion flow? In this talk, I shall present first ever attempted three dimensional global GRMHD simulations to shed light on the effects of magnetic field configurations onto the dynamics of accretion flows. Based on this study, I will be advocating for a need for a strong magnetic field in theoretical models to explain several observational features of accreting black holes. Additionally, I will talk about how nature could produce the required strong magnetic field without artificially injecting it in our models. I will conclude the presentation with one of the most interesting features of time variability originating due to the GR effects of the black hole. This time variability is observed in X-ray emission from accretion disks and remains fixed for a given system. Using a series of numerical simulations, I will give a theoretical explanation of what could cause such a harmony in one of the most energetic and complex systems.

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