Equilibrium Initialization and Stability of Three-Dimensional Gas Disks

Details Equilibrium Initialization and Stability of Three-Dimensional Gas Disks Equilibrium Initialization and Stability of Three-Dimensional Gas Disks

2010-04-30

arxiv.org/abs/1004.5593v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

17 pages, 10 figures, accepted by MNRAS

Scientific paper

We present a new systematic way of setting up galactic gas disks based on the assumption of detailed hydrodynamic equilibrium. To do this, we need to specify the density distribution and the velocity field which supports the disk. We first show that the required circular velocity has no dependence on the height above or below the midplane so long as the gas pressure is a function of density only. The assumption of disks being very thin enables us to decouple the vertical structure from the radial direction. Based on that, the equation of hydrostatic equilibrium together with the reduced Poisson equation leads to two sets of second-order non-linear differential equation, which are easily integrated to set-up a stable disk. We call one approach `density method' and the other one `potential method'. Gas disks in detailed balance are especially suitable for investigating the onset of the gravitational instability. We revisit the question of global, axisymmetric instability using fully three-dimensional disk simulations. The impact of disk thickness on the disk instability and the formation of spontaneously induced spirals is studied systematically with or without the presence of the stellar potential. In our models, the numerical results show that the threshold value for disk instability is shifted from unity to 0.69 for self-gravitating thick disks and to 0.75 for combined stellar and gas thick disks. The simulations also show that self-induced spirals occur in the correct regions and with the right numbers as predicted by the analytic theory.

Affiliated with

Also associated with

No associations

Rating

Equilibrium Initialization and Stability of Three-Dimensional Gas Disks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Equilibrium Initialization and Stability of Three-Dimensional Gas Disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Equilibrium Initialization and Stability of Three-Dimensional Gas Disks will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-388775