Hamburg 2016 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 5: Classical General Relativity I

GR 5.6: Talk

Tuesday, March 1, 2016, 15:25–15:40, VMP6 HS A

A general pseudo-Newtonian limit of geodesic motion — •Vojtech Witzany — ZARM, Universität Bremen, Am Fallturm, 28359 Bremen, Germany

Almost from the very first investigations into the nature of black-hole accretion, astrophysicists have used "pseudo-Newtonian" potentials to describe the dynamics of accretion discs. These potentials seamlessly reduce to the Newtonian gravitational potential in the far-field limit, but posses simple modifications in the close field to mimic some of the key features of particle motion near a black hole.

Recently, a new class of elegantly derived and accurate velocity-dependent potentials emerged in the literature raising the question whether there is a general pseudo-Newtonian description for any space-time. In this talk, I will show that there is such a description both for massive and massless particle motion, and that this description can give exact coordinate-time-parametrized null geodesics in stationary space-times. Futhermore, I will demonstrate the effectivity of this description in the Kerr space-time.