Kinematics of galaxies in Compact Groups. Studying the B-band Tully-Fisher relation

Abstract

We obtained new Fabry-Perot data cubes and derived velocity fields, monochromatic and velocity dispersion maps for 28 galaxies in the Hickson compact groups 37, 40, 47, 49, 54, 56, 68, 79 and 93. We find that one third of the non-barred compact group galaxies have position angle misalignments between the stellar and gaseous components. This and the asymmetric rotation curves are clear signatures of kinematic perturbations, probably due to interactions among compact group galaxies. A comparison between the B-band Tully-Fisher relation for compact group galaxies and that for the GHASP field-galaxy sample shows that, despite the high fraction of compact group galaxies with asymmetric rotation curves, these lie on the Tully-Fisher relation defined by galaxies in less dense environments, although with more scatter. This is in agreement with previous results, but now confirmed for a larger sample of 41 galaxies. We confirm the tendency for compact group galaxies at the low-mass end of the Tully-Fisher relation (HCG 49b, 89d, 96c, 96d and 100c) to have either a magnitude that is too bright for its mass (suggesting brightening by star formation) and/or a low maximum rotational velocity for its luminosity (suggesting tidal stripping). These galaxies are outside the Tully Fisher relation, at the 1 sigma level, even when the minimum acceptable values of inclinations are used to compute their maximum velocities. The inclusion of such galaxies with v<100 km/s in the determination of the zero point and slope of the compact group B-band Tully-Fisher relation would strongly change the fit, making it different from the relation for field galaxies, a fact that has to be kept in mind when studying scaling relations of interacting galaxies, specially at high redshifts.

17 figures. Accepted for publication in Astronomy and Astrophysics. Hickson compact groups Fabry-Perot data are available at http://fabryperot.oamp.fr/PerotFabry/

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Cited by in corpus (7)

• Compact Groups of Galaxies selected by stellar mass: The 2MASS Compact Group Catalogue
• Galaxy Interactions in Compact Groups II: abundance and kinematic anomalies in HCG 91c
• Star-forming regions and the metallicity gradients in the tidal tails: The case of NGC 92
• The H$\alpha$ kinematics of interacting galaxies in 12 compact groups
• The star formation histories of Hickson compact group galaxies
• The Tully-Fisher relations for Hickson Compact Group galaxies
• Star-Forming Compact Groups (SFCGs): An ultraviolet search for a local sample