Inter-disks inversion surfaces

• Published in: The European physical journal. C, Particles and fields Vol. 84; no. 10; pp. 1 - 25
• Main Authors: Pugliese, D., Stuchlík, Z.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 18.10.2024; SpringerOpen
• Subjects: Astronomy; Astrophysics and Cosmology; Elementary Particles; Hadrons; Heavy Ions; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Regular Article - Theoretical Physics; String Theory
• ISSN: 1434-6052; 1434-6052
• DOI: 10.1140/epjc/s10052-024-13457-3

We consider a counter-rotating torus orbiting a central Kerr black hole ( BH ) with dimensionless spin a , and its accretion flow into the BH , in an agglomerate of an outer counter-rotating torus and an inner co-rotating torus. This work focus is the analysis of the inter-disks inversion surfaces. Inversion surfaces are spacetime surfaces, defined by the condition u ϕ = 0 on the flow torodial velocity, located out of the BH ergoregion, and totally embedding the BH . They emerge as a necessary condition, related to the spacetime frame-dragging, for the counter-rotating flows into the central Kerr BH . In our analysis we study the inversion surfaces of the Kerr spacetimes for the counter-rotating flow from the outer torus, impacting on the inner co-rotating disk. Being totally or partially embedded in (internal to) the inversion surfaces, the inner co-rotating torus (or jet) could be totally or in part “shielded”, respectively, from the impact with flow with a u ϕ < 0 . We prove that, in general, in the spacetimes with a < 0.551 the co-rotating toroids are always external to the accretion flows inversion surfaces. For 0.551 < a < 0.886 , co-rotating toroids could be partially internal (with the disk inner region, including the inner edge) in the flow inversion surface. For BHs with a > 0.886 , a co-rotating torus could be entirely embedded in the inversion surface and, for larger spins, it is internal to the inversion surfaces. Tori orbiting in the BH outer ergoregion are a particular case. Further constraints on the BHs spins are discussed in the article.