Kinematics of M51-type interacting galaxies

• Main Authors: Gunthardt, G, Díaz, R. J, Aguero, M. P
• Format: Journal Article
• Language: English
• Published: 30-07-2016
• Subjects: Physics - Astrophysics of Galaxies
• DOI: 10.48550/arxiv.1605.02842

We present a kinematic catalogue for 21 M51-type galaxies. It consists of
radial velocity distributions observed with long slit spectroscopy along
different position angles, for both the main and satellite components. We
detect deviations from circular motion in most of the main galaxies of each
pair, due to the gravitational perturbation produced by the satellite galaxy.
However some systems do not show significant distortions in their radial
velocity curves. We found some differences between the directions of the
photometric and kinematic major axes in the main galaxies with a bar subsystem.
The Tully-Fisher relation in the B-band and Ks-band for the present sample of
M51-type systems is flatter when compared with isolated galaxies. Using the
radial velocity data set, we built a synthetic normalized radial velocity
distribution, as a reference for future modeling of these peculiar systems. The
synthetic rotation curve, representing the typical rotation curve of the main
galaxy in an M51-type pair, is near to solid body-like inside 4 kpc, and then
is nearly flat within the radial range 5-15 kpc. The relative position angles
between the main galaxy major axis and the companion location, as well as the
velocity difference amplitude, indicate that the orbital motion of the
satellite has a large projection on the main galaxy equatorial plane. In
addition, the radial velocity differences between the two galaxies indicate
that the satellite orbital motion is within the range of amplitudes of the main
galaxy rotation curve and all the M51-type systems studied here except for one,
are gravitationally bounded.