The interacting galaxy pair KPG 390: H$\alpha$ kinematics

TL;DR

This study uses H-alpha Fabry-Perot observations to analyze the kinematics of the interacting galaxy pair NGC 5278/79, deriving velocity fields, rotation curves, and dark matter profiles, and determining the spiral nature of both galaxies.

Contribution

It provides detailed kinematic analysis of NGC 5278/79, compares dark matter halo models, and confirms both galaxies are trailing spirals, using new Fabry-Perot H-alpha data.

Findings

Rotation curves fitted with three halo models show similar quality.

Pseudo-isothermal halo requires significantly less dark matter.

Both galaxies are confirmed as trailing spirals.

Abstract

In this work we present scanning Fabry-Perot H$\alpha$ observations of the isolated interacting galaxy pair NGC 5278/79 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields and rotation curves for both galaxies. For NGC 5278 we also obtained the residual velocity map to investigate the non-circular motions, and estimated its mass by fitting the rotation curve with a disk+halo components. We test three different types of halo (pseudo-isothermal, Hernquist and Navarro Frenk White) and obtain satisfactory fits to the rotation curve for all profiles. The amount of dark matter required by pseudo-isothermal profile is about ten times smaller than, that for the other two halo distributions. Finally, our kinematical results together with the analysis of dust lanes distribution and of surface brightness profiles along the minor axis allowed us to determine univocally that both components of the interacting pair are trailing spirals.