H{\alpha} Kinematics of S4G spiral galaxies-I. NGC 864

TL;DR

This study analyzes the kinematics of the isolated spiral galaxy NGC 864 using Hα Fabry-Perot data, revealing asymmetries caused by non-circular motions and characterizing the galaxy's rotation, bar, spiral arms, and star formation activity.

Contribution

First detailed kinematic analysis of NGC 864 combining Fabry-Perot data with multi-wavelength imaging to understand its dynamical features.

Findings

Asymmetries in velocity field due to non-circular motions in the bar zone

Flat-profile bar consistent with strong bar and grand design spiral pattern

Star formation concentrated in the two spiral arms

Abstract

We present a study of the kinematics of the isolated spiral galaxy NGC 864, using H{\alpha} Fabry-Perot data obtained with the GH{\alpha}FaS instrument at the William Herschel Telescope in La Palma, complemented with images at 3.6 {\mu}m, in the R band and in H{\alpha} filter, and integral field spectroscopic data. The resulting data cubes and velocity maps allow the study of the kinematics of the galaxy, including in-depth investigations of the rotation curve, velocity moment maps, velocity residual maps, gradient maps and position-velocity diagrams. We find asymmetries in the velocity field in the bar zone, caused by non-circular motions, probably in response to the potential of the bar. We also find a flat-profile bar, in agreement with the strong bar, with the grand design spiral pattern, and with the gap between the ends of the bar and the start of the spiral arms. We quantify the rate of massive star formation, which is concentrated in the two spiral arms.