A phase lag between disc and corona in GRMHD simulations of precessing tilted accretion discs

M. Liska*, C. Hesp, A. Tchekhovskoy, A. Ingram, M. van der Klis, S. B. Markoff

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

In the course of its evolution, a black hole (BH) accretes gas from a wide range of directions. Given a random accretion event, the typical angular momentum of an accretion disc would be tilted by ∼60 relative to the BH spin. Misalignment causes the disc to precess at a rate that increases with BH spin and depends on disc morphology. We present general-relativistic magnetohydrodynamic (GRMHD) simulations spanning a full precession period of highly tilted (60), moderately thin (h/r=0.1) accretion discs around a rapidly spinning (a≃0.9) BH. While the disc and jets precess in phase, we find that the disc wind/corona, sandwiched between the two, lags behind by ≳10°. For spectral models of BH accretion, the implication is that hard non-thermal (corona) emission lags behind the softer (disc) emission, thus potentially explaining some properties of the hard energy lags seen in Type-C low frequency quasi-periodic oscillations in X-ray binaries. While strong jets are unaffected by this disc-corona lag, weak jets can stall when encountering the lagging corona at distances r∼100 BH radii. This interaction may quench large-scale jet formation.

Original languageEnglish (US)
Article number102012
JournalNew Astronomy
Volume101
DOIs
StatePublished - Jul 2023

Funding

We thank Marta Volonteri for useful feedback. This research was made possible by NSF PRAC award no. 1615281 and OAC-1811605 at the Blue Waters sustained-petascale computing project. ML and MK were supported by the NWO Spinoza Prize, AI by the Royal Society URF, and SM by the NWO VICI grant (no. 639.043.513). ML was also supported by the John Harvard and ITC fellowships. Supporting information, Additional Supporting Information may be found in the online version of this article: movie files. See our YouTube playlist for 3D visualizations of all models. We thank Marta Volonteri for useful feedback. This research was made possible by NSF PRAC award no. 1615281 and OAC-1811605 at the Blue Waters sustained-petascale computing project. ML and MK were supported by the NWO Spinoza Prize , AI by the Royal Society URF , and SM by the NWO VICI grant (no. 639.043.513 ). ML was also supported by the John Harvard and ITC fellowships.

Keywords

  • Accretion, accretion discs
  • Black hole physics
  • Galaxies: jets
  • MHD
  • Methods: numerical

ASJC Scopus subject areas

  • Instrumentation
  • Astronomy and Astrophysics
  • Space and Planetary Science

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