Simulations of Jets Driven by Black Hole Rotation

Abstract

The origin of jets emitted from black holes is not well understood, however there are two possible energy sources, the accretion disk or the rotating black hole. Magnetohydrodynamic simulations show a well-defined jet that extracts energy from a black hole. If plasma near the black hole is threaded by large-scale magnetic flux, it will rotate with respect to asymptotic infinity creating large magnetic stresses.These stresses are released as a relativistic jet at the expense of black hole rotational energy. The physics of the jet initiation in the simulations is described by the theory of black hole gravitohydromagnetics.Most quasars radiate a small fraction of their emission in the radio band (radio quiet), yet about 10% launch powerful radio jets (a highly collimated beam of energy and particles) with kinetic luminosities rivalling or sometimes exceeding the luminosity of the quasar host (radio loud).1 There is currently no clear theoretical understanding of the physics that occasionally switches on these powerful beams of energy in quasars.Powerful extragalactic radio sources tend to be associated with large elliptical galaxy host that harbour supermassive black holes (~10 9 M0). 2 The synchrotron emitting jets are clearly highly magnetized and appe ar to emanate from the environs of the central black hole, within the resolution limits of very long baseline interferometry (VLBI).Observations (see the supplementary file) indicate that jets emitted from supermassive black hole magnetospheres are likely required for any theory to be in accord with the data. 2,3,4 Previous perfect magnetohydrodynamic (MHD hereafter) simulations of entire black hole magnetospheres have shown some suggestive results. For example, the 2 simulations of [5] were the first to s how energy extraction from the black hole, but there was no outflow of plasma. Numerical models of an entire magnetosphere involve a complex set of equations that reflect the interaction of the background space-time with the plasma. In many instances, the only way to get any time evolution of the magnetosphere is to assume unphysical initial conditions. 5,6,9,10 Even so, previous simulations have not shown a black hole radiating away its potential energy into a pair of bipolar jets. 5,6,7,8,9,10 Most importantly, in previous efforts the underlying physics is masked by the complexity of the simulation. Thus, this numerical work has done little to clarify the fundamental physics that couples the jet to the black hole.We exploit the simplification that the full set of MHD equations in curved spacetime indicate that a magnetized plasma can be regarded as a fluid composed of nonlinear strings in which the strings are mathematically equivalent to thin magnetic flux tubes. 11,12 In this treatment, a flux tube is thin by definition if the pressure variations across the flux tube is negligible compared to the total external pressure (gas plus magnetic), P, that represents the effects of the enveloping magnetized plasma (the magnetosphere). By concentrating ...

3C 216: A Powerful FR II Seyfert 1 Galaxy

“…However, a large-scale magnetic flux trapped in the vortex inside the accretion disk can tap the black hole rotational energy, as seen in the MHD numerical simulations of Hawley & Krolik (2006), McKinney (2005, McKinney &Gammie (2004), andSemenov et al (2004). Yet, it is not a trivial matter to obtain the condition.…”

“…As a consequence of the near-independence of the UV spectrum on the radio state (de Vries et al 2006;Corbin & Francis 1994), it has been argued that the black hole and not the accretion disk is the power source for FR II jets (Semenov et al 2004). However, a large-scale magnetic flux trapped in the vortex inside the accretion disk can tap the black hole rotational energy, as seen in the MHD numerical simulations of Hawley & Krolik (2006), McKinney (2005, McKinney &Gammie (2004), andSemenov et al (2004).…”

“…Yet, it is not a trivial matter to obtain the condition. Semenov et al (2004) is based on large-scale magnetic flux that threads the equatorial plane of the ergosphere, the active region outside of the black hole. The solutions attain a maximum R value, , that was calculated for rapidly rotating black holes, R max in equation ( …”

Multi-resonance orbital model of high-frequency quasi-periodic oscillations: possible high-precision determination of black hole and neutron star spin

“…When the pressure gradients in thick tori become important as the restoring force, the radial oscillation frequency strongly differs from the radial geodetical epicyclic frequency (Rezzolla et al 2003b,a;Montero et al 2004), similar to the model of oscillating string loops where the string tension due to magnetic field is the main restoring force (Stuchlík & Kološ 2012b,a;Jacobson & Sotiriou 2009;Semenov et al 2004;Spruit 1981).…”

Dynamics of an electric current-carrying string loop near a Schwarzschild black hole embedded in an external magnetic field

“…Current carrying strings moving axisymmetrically along the axis of a Kerr black hole [1], a Schwarzschild-de Sitter black hole [2,3], or a braneworld black hole or naked singularity [4] could represent a toy model of plasma that exhibits associated stringlike behavior via dynamics of the magnetic field lines in the plasma [5][6][7][8] or due to thin isolated flux tubes of plasma that could be described by an one-dimensional string [9]. Tension of such a string loop prevents its expansion beyond some radius, while its world sheet current introduces an angular momentum barrier preventing the loop from collapsing into the black hole.…”