Acceleration of 2D Relativistic Jets

Gas accretion onto compact objects such as neutron stars and black holes is the most efficient source of energy extraction in the universe and has been recognized as the driving force behind some of the most energetic astrophysical phenomena giving rise to active galaxies (AGN), neutron star collisions, gamma-ray bursts (GRBs), X-ray binaries (XRBs), and many other transient sources. A whirlpool of gas falling into the potential well of a black hole can liberate a substantial fraction of gas rest mass energy in the form of radiation, radiation and magnetically driven outflows and magnetized jets. While nuclear fusion has a rest-mass to energy conversion efficiency on the order of one percent, accretion efficiency typically ranges between 5−100 percent. Jets and outflows regulate the growth of galaxies and the formation of stars through black hole feedback.

Not only the formation, but also the acceleration of such jets is important for understanding black hole feedback. Me and Koushik Chatterjee conducted the first 2D GRMHD simulations of relativistic jets extending over more than 5 orders of magnitude in time and distance. We found, as shown in the video, that shear motions between the jet and ambient medium can contribute to the variability in AGN jets detected by various ground and space based observatories. In addition, we found that mass from the ambient medium can get entrained in the jet, which has consequences for the acceleration profile of astrophysical jets.

Acceleration of 3D Relativistic Jets

We are now in the final stages of setting up simulations of relativistic in 3D to study how an external ambient medium can induce kink (sideways motion) and pinch (compression) instabilities potentially responsible for injecting energy into the ambient medium. This can happen in the context of supermassive black hole feedback which heats up galaxies and clusters, and in the context of collapsars after a massive star that collapses into a black hole and binary mergeres. Below you see a 2-dimensional snapshot of a large-scale 3D GRMHD simulation of a relativistic jets performed by Ore Gottlieb with H-AMR in the context of a collapsar. The disk and black hole are tilted by 90 degrees with respect of the z-axis for numerical reasons. The jet forms various pinch and kink modes which makes the jet appear wider than it actually is.

Publications

1) Accelerating AGN jets to parsec scales using general relativistic MHD simulations

2) Black Hole to Photosphere: 3D GRMHD Simulations of Collapsars Reveal Wobbling and Hybrid Composition Jets

3) On the Jet-Ejecta Interaction in 3D GRMHD Simulations of a Binary Neutron Star Merger Aftermath

4) Black hole to breakout: 3D GRMHD simulations of collapsar jets reveal a wide range of transients

5) Bridging the Bondi and Event Horizon Scales: 3D GRMHD Simulations Reveal X-shaped Radio Galaxy Morphology

6) Jet Formation in 3D GRMHD Simulations of Bondi-Hoyle-Lyttleton Accretion