Analytic gas orbits in an arbitrary rotating galactic potential using the linear epicyclic approximation
Version of Record online: 31 JAN 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 421, Issue 2, pages 1089–1102, April 2012
How to Cite
Piñol-Ferrer, N., Lindblad, P. O. and Fathi, K. (2012), Analytic gas orbits in an arbitrary rotating galactic potential using the linear epicyclic approximation. Monthly Notices of the Royal Astronomical Society, 421: 1089–1102. doi: 10.1111/j.1365-2966.2011.20367.x
- Issue online: 16 MAR 2012
- Version of Record online: 31 JAN 2012
- Accepted 2011 December 10. Received 2011 December 9; in original form 2011 November 14
- galaxies: kinematics and dynamics;
- galaxies: spiral
A code, epic5, has been developed which computes, in the two-dimensional case, the initially circular orbits of guiding centra in an arbitrary axisymmetric potential with an arbitrary, weak perturbing potential in solid body rotation. This perturbing potential is given by its Fourier expansion. The analytic solution solves the linear epicyclic approximation of the equations of motion. To simulate the motion of interstellar matter and to damp the Lindblad resonances, in these equations we have introduced a friction which is proportional to the deviation from circular velocity. The corotation resonance is also damped by a special parameter. The program produces, in just a few seconds, orbital and density maps, as well as line-of-sight velocity maps for a chosen orientation of the galaxy.
We test epic5 by comparing its results with previous simulations and observations from the literature, which gives satisfactory agreement. The aim is that this program should be a useful complement to elaborate numerical simulations. Particularly so are its abilities to quickly explore the parameter space, to construct artificial galaxies and to isolate various single agents important for developing the structure of interstellar matter in disc galaxies. The epic5 code can be obtained from email@example.com.