Department

Physics

Document Type

Article

Publication Date

6-6-2017

Embargo Period

6-6-2018

Abstract

The idea that black hole spin is instrumental in the generation of powerful jets in active galactic nuclei and X-ray binaries is arguably the most contentious claim in black hole astrophysics. Because jets are thought to originate in the context of electromagnetism, and the modeling of Maxwell fields in curved spacetime around black holes is challenging, various approximations are made in numerical simulations that fall under the guise of ‘ideal magnetohydrodynamics’. But the simplifications of this framework may struggle to capture relevant details of real astrophysical environments near black holes. In this work, we highlight tension between analytic and numerical results, specifically between the analytically derived conserved Noether currents for rotating black hole spacetimes and the results of general relativistic numerical simulations (GRMHD). While we cannot definitively attribute the issue to any specific approximation used in the numerical schemes, there seem to be natural candidates, which we explore. GRMHD notwithstanding, if electromagnetic fields around rotating black holes are brought to the hole by accretion, we show from first principles that prograde accreting disks likely experience weaker large-scale black hole-threading fields, implying weaker jets than in retrograde configurations.

Journal

Astrophysics and Space Science

Journal ISSN

0004-640X

Volume

362

Issue

121

Digital Object Identifier (DOI)

10.1007/s10509-017-3108-x

Comments

See http://dx.doi.org/10.1007/s10509-017-3108-x for the article before embargo ends.

Available for download on Wednesday, June 06, 2018

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