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Title: VARIABILITY FROM NON-AXISYMMETRIC FLUCTUATIONS INTERACTING WITH STANDING SHOCKS IN TILTED BLACK HOLE ACCRETION DISKS

We study the spatial and temporal behavior of fluid in fully three-dimensional, general relativistic, magnetohydrodynamical simulations of both tilted and untilted black hole accretion flows. We uncover characteristically greater variability in tilted simulations at frequencies similar to those predicted by the formalism of trapped modes, but ultimately conclude that its spatial structure is inconsistent with a modal interpretation. We find instead that previously identified, transient, overdense clumps orbiting on roughly Keplerian trajectories appear generically in our global simulations, independent of tilt. Associated with these fluctuations are acoustic spiral waves interior to the orbits of the clumps. We show that the two non-axisymmetric standing shock structures that exist in the inner regions of these tilted flows effectively amplify the variability caused by these spiral waves to markedly higher levels than in untilted flows, which lack standing shocks. Our identification of clumps, spirals, and spiral-shock interactions in these fully general relativistic, magnetohydrodynamical simulations suggests that these features may be important dynamical elements in models that incorporate tilt as a way to explain the observed variability in black hole accretion flows.
Authors:
 [1] ;  [2] ;  [3]
  1. Natural Science Division, Pepperdine University, Malibu, CA 90263 (United States)
  2. Department of Physics, University of California, Santa Barbara, CA 93106 (United States)
  3. Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States)
Publication Date:
OSTI Identifier:
22140060
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 761; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ASTRONOMY; ASTROPHYSICS; AXIAL SYMMETRY; BLACK HOLES; COMPUTERIZED SIMULATION; FLUCTUATIONS; MAGNETOHYDRODYNAMICS; ORBITS; RELATIVISTIC RANGE; THREE-DIMENSIONAL CALCULATIONS; TRANSIENTS; TRAPPING; TURBULENCE; X RADIATION