Year: 2019
Type: article
Abstract: ABSTRACT Accreting black holes produce collimated outflows, or jets, that traverse many orders of magnitude in distance, accelerate to relativistic velocities, and collimate into tight opening angles. Of these, perhaps the least understood is jet collimation due to the interaction with the ambient medium. In order to investigate this interaction, we carried out axisymmetric general relativistic magnetohydrodynamic simulations of jets produced by a large accretion disc, spanning over 5 orders of magnitude in time and distance, at an unprecedented resolution. Supported by such a disc, the jet attains a parabolic shape, similar to the M87 galaxy jet, and the product of the Lorentz factor and the jet half-opening angle, γθ ≪ 1, similar to values found from very long baseline interferometry (VLBI) observations of active galactic nuclei (AGNs) jets; this suggests extended discs in AGNs. We find that the interaction between the jet and the ambient medium leads to the development of pinch instabilities, which produce significant radial and lateral variability across the jet by converting magnetic and kinetic energy into heat. Thus pinched regions in the jet can be detectable as radiating hotspots and may provide an ideal site for particle acceleration. Pinching also causes gas from the ambient medium to become squeezed between magnetic field lines in the jet, leading to enhanced mass loading and deceleration of the jet to non-relativistic speeds, potentially contributing to the spine-sheath structure observed in AGN outflows.
Authors: K Chatterjee, M Liska, A Tchekhovskoy, S B Markoff
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,046
Awards: G258938352, From micro- to mega-scales: understanding how black holes shape the local Universe, G3825489461, Collaborative Research: WoU-MMA: Multi-scale and multi-messenger modeling of jets in active galactic nuclei, Collaborative Research: WoU-MMA: Multi-Scale and Multi-Messenger Modeling of Jets in Active Galactic Nuclei, G5130244574, GPU-Enabled General Relativistic Simulations of Misaligned Black Hole Accretion Systems, WE PROPOSE TO USE STATE-OF-THE ART NUMERICAL SIMULATIONS OF NSBH AND NSNS MERGERS AND OF THEIR POST-MERGER REMNANTS TO INFORM OBSERVATIONS OF THESE SYSTEMS. WE WILL FOCUS ON PREDICTING THE PROPERTIES OF THE EJECTED MATERIAL A CRITICAL STEP IN THE MODELING OF KILONOVAE AND IN THE DETERMINATION OF THE IMPACT OF MERGERS ON THE ENRICHMENT OF THE UNIVERSE IN HEAVY ELEMENTS. A BIG CHALLENGE IN MODELING THESE OUTFLOWS IS THAT THEY ARE PRODUCED OVER A WIDE RANGE OF TIME SCALES. MATERIAL IS FIRST EJECTED DYNAMICALLY DURING THE MERGER (OVER A FEW MILLISECONDS) THEN THROUGH POWERFUL DISK WINDS (OVER 100 MS) AND FINALLY THROUGH THE VISCOUS EVOLUTION OF THE REMNANT ACCRETION DISK (OVER 10 S). WE WILL PERFORM FOR THE FIRST TIME 3D SIMULATIONS CAPABLE OF CAPTURING ALL THREE COMPONENTS OF THE EJECTA WITH SELF-CONSISTENT EVOLUTION FROM BEFORE THE MERGER UNTIL MASS OUTFLOWS BECOMES NEGLIGIBLE., Collaborative Research: Short Gamma-Ray Bursts Arising From Misaligned Structured Jets in the Dawn of Gravitational Wave Astronomy, G603814699, Collaborative Research: WoU-MMA: Multi-scale and multi-messenger modeling of jets in active galactic nuclei, Kavli Institute for Theoretical Physics, GPU-enabled General Relativistic Simulations of Jetted Tidal Disruptions of Stars by Supermassive Black Holes, G8629006955
OpenAlex ID: W2928227044