Simple and accurate modelling of the gravitational potential produced by thick and thin exponential discs

Smith, R.; Flynn, C.; Candlish, G. N.; Fellhauer, M.; Gibson, B. K.

Abstract

We present accurate models of the gravitational potential produced by a radially exponential disc mass distribution. The models are produced by combining three separate Miyamoto–Nagai discs. Such models have been used previously to model the disc of the Milky Way, but here we extend this framework to allow its application to discs of any mass, scalelength, and a wide range of thickness from infinitely thin to near spherical (ellipticities from 0 to 0.9). The models have the advantage of simplicity of implementation, and we expect faster run speeds over a double exponential disc treatment. The potentials are fully analytical, and differentiable at all points. The mass distribution of our models deviates from the radial mass distribution of a pure exponential disc by <0.4 per cent out to 4 disc scalelengths, and <1.9 per cent out to 10 disc scalelengths. We tabulate fitting parameters which facilitate construction of exponential discs for any scalelength, and a wide range of disc thickness (a user-friendly, web-based interface is also available). Our recipe is well suited for numerical modelling of the tidal effects of a giant disc galaxy on star clusters or dwarf galaxies. We consider three worked examples; the Milky Way thin and thick disc, and a discy dwarf galaxy.

Citation

Smith, R., Flynn, C., Candlish, G. N., Fellhauer, M., & Gibson, B. K. (2015). Simple and accurate modelling of the gravitational potential produced by thick and thin exponential discs. Monthly notices of the Royal Astronomical Society, 448(3), 2934-2940. https://doi.org/10.1093/mnras/stv228

• Journal Article Type: Article
• Acceptance Date: Feb 2, 2015
• Online Publication Date: Mar 5, 2015
• Publication Date: Apr 11, 2015
• Deposit Date: Mar 9, 2016
• Publicly Available Date: Mar 9, 2016
• Journal: Monthly notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 448
• Issue: 3
• Pages: 2934-2940
• DOI: https://doi.org/10.1093/mnras/stv228
• Keywords: Methods : numerical, Galaxies : kinematics and dynamics
• Public URL: https://hull-repository.worktribe.com/output/412512
• Publisher URL: http://mnras.oxfordjournals.org/content/448/3/2934
• Additional Information: This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.