Modelling vertical structure in circular velocity of spiral galaxy NGC 4244

Abstract

We study the vertical gradient in azimuthal velocity of spiral galaxy NGC 4244 in a thin disk model. With surface density accounting for the rotation curve, we model the gradient properties in the approximation of quasi-circular orbits and find the predictions to be consistent with the gradient properties inferred from measurements. This consistency may suggest that the mass distribution in this galaxy is flattened.

Magnetic Fields in Diffuse Media

“…A large radial scale length may mean that magnetic fields affect the global rotation of the gas in the outer parts of spiral galaxies (Jałocha et al 2012;, but this cannot explain the flat rotation curves (Elstner et al 2014). The resulting value of ' 16 kpc is a lower limit because the cosmic-ray electrons lose their energy with distance from the star-forming disk and the equipartition assumption yields too small values for the field strength.…”