Hickson 62.I. Kinematics of NGC4778

Abstract

Detailed studies of the photometric and kinematical properties of compact groups of galaxies are crucial to understand the physics of galaxy interactions and to shed light on some aspects of galaxy formation and evolution. In this paper we present a kinematical and photometrical study of a member, NGC4778, of the nearest (z=0.0137) compact group: Hickson 62. Aims: The aim of this work was to investigate the existence of kinematical anomalies in the brightest group member, NGC4778 in order to constrain the dynamical status and the formation history of the group. Methods: We used long-slit spectra obtained with FORS1 at VLT, to measure line-of-sight velocity distributions by means of the Fourier Correlation Quotient method, and to derive the galaxy rotation curve and velocity dispersion profile. Results: Our analysis reveals that Hickson 62a, also known as NGC4778, is an S0 galaxy with kinematical and morphological peculiarities, both in its central regions (r < 5'') and in the outer halo. In the central regions, the rotation curve shows the existence of a kinematically decoupled stellar component, offset with respect to the photometric center. In the outer halo we find an asymmetric rotation curve and a velocity dispersion profile showing a rise on the SW side, in direction of the galaxy NGC4776. Conclusions: The nuclear counterrotation, the distorted kinematics in the outer halo and the X-ray properties of the group suggest that NGC4778 may be the product of a recent minor merger, more reliable with a small late-type galaxy.

arXiv comment18 pages, 8 figures, accepted for pubblication in Astronomy and Astrophysics

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Cited by in corpus (10)

• Testing the Low-Mass End of X-Ray Scaling Relations with a Sample of Chandra Galaxy Groups
• The Infrared Properties of Hickson Compact Groups
• Deep high-resolution X-ray spectra from cool-core clusters
• Cavities and shocks in the galaxy group HCG 62 as revealed by Chandra, XMM and GMRT data
• Improved measurements of turbulence in the hot gaseous atmospheres of nearby giant elliptical galaxies
• A Deep Chandra Observation of the AGN Outburst and Merger in Hickson Compact Group 62
• Suzaku Observation of HCG 62: Temperature, Abundance, and Extended Hard X-ray Emission Profiles
• VLA Radio Study of a Sample of Nearby X-ray and Optically Bright Early-Type Galaxies
• A High-Abundance Arc in the Compact Group of Galaxies HCG 62: An AGN- or Merger-Induced Metal Outflow?
• A Study of the Merger History of the Galaxy Group HCG 62 Based on X-Ray Observations and SPH Simulations