http://arxiv.org/abs/1706.08615
Assuming a vertical hydrostatic equilibrium between different baryonic disk components, Poisson’s equations were set up and solved numerically to obtain the molecular scale height in the spiral galaxy NGC 7331. The scale height of the molecular disk was found to vary between $\sim 100-200$ pc depending on radius and assumed velocity dispersion of the molecular gas. The solutions of the hydrostatic equation and the rotation curve were used to produce a dynamical model and a total intensity map of the molecular disk. The modelled and the observed molecular disk matches with each other to a large extent. However, the modelled molecular disk falls short in producing observed projected thickness, specially at the central region. The velocity dispersion of the molecular disk is found to have no detectable influence on the projected thickness and hence can not account for the discrepancy in the thickness. A change in the inclination also found to be incapable of eliminating the difference completely. The molecular disk of NGC 7331 was projected to an inclination of 90$^o$ to estimate its observable edge-on thickness, which was found to be $\sim$ 2 kpc. Our result indicates that a simple hydrostatic condition is capable of explaining thick molecular disks observed in external galaxies.
N. Patra
Wed, 28 Jun 17
-48/62
Comments: Submitted to MNRAS