Velocity dispersion as a factor modifying the distribution of mass in disk-like galaxies -- an example of galaxy UGC 6446

TL;DR

This paper presents an iterative method to determine the mass distribution in disk-like galaxies by incorporating velocity dispersion, demonstrating its impact on the mass-to-light ratio and mass component analysis in galaxy UGC 6446.

Contribution

It generalizes previous methods to include velocity dispersion effects, providing a more accurate analysis of galactic mass distribution from rotation curves.

Findings

Velocity dispersion influences local mass-to-light ratios.

Inclusion of velocity dispersion reduces the estimated mass-to-light ratio at galaxy outskirts.

Method applied to UGC 6446 shows significant effects on mass distribution modeling.

Abstract

Within the disk model framework used to approximately describe flattened galaxies, we develop an iterative method of determining column mass density from rotation curve supplemented with isotropic velocity dispersion profile. This generalizes our previous iterative method to the case when the velocity dispersion becomes important. We show on the example of UGC 6446 galaxy, that taking the velocity dispersion into account results in some observational signatures in the behavior of the local mass-to-light ratio. Along with galactic magnetic fields, this is another factor allowing to substantially reduce the local mass-to-light ratio at galactic outskirts. Taking the velocity dispersion into account may also have some consequences for the division of mass distribution between various mass components in modeling rotation curves.