Is HCG31 undergoing a merger or a fly-by interaction?

Abstract

We present Fabry-Perot and multi-object spectroscopy of the galaxies in Hickson compact group 31 (HCG31). Based upon our H$\alpha$ data cubes, galaxies A and C are a single entity, showing no discontinuity in their kinematics. Kinematically, galaxy E is probably a component of the A+C complex; otherwise it is a recently detached fragment. Galaxy F appears, both kinematically and chemically, to have formed from material tidally removed from the A+C complex. Galaxies B and G are kinematically distinct from this complex. Galaxy Q also has a radial velocity compatible with group membership. Galaxies A, B, C, and F have nearly identical oxygen abundances, despite spanning a luminosity range of 5mag. Galaxy B's oxygen abundance is normal for its luminosity, while galaxy F's abundance is that expected given its origin as a tidal fragment of the A+C complex. The oxygen abundances in galaxies A and C are also understandable if the A+C complex is a late-type spiral suffering strong gas inflow and star formation as a result of a tidal interaction. Given the kinematics of both the galaxies and the \ion{H}{i} gas, the oxygen abundances, and the position of galaxy G, we propose that an interaction of galaxy G with the A+C complex, rather than a merger of galaxies A and C, is a more complete explanation for the tidal features and other properties of HCG31. In this case, the A+C complex need not be a merger in progress, though this is not ruled out.

accepted for publication by Astronomy & Astrophysics

References in corpus (14)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Star Formation in Galaxies Along the Hubble Sequence
• Correcting for the Effects of Interstellar Extinction
• Gasdynamics and Starbursts in Major Mergers
• The HST Key Project on the Extragalactic Distance Scale. XXVIII. Combining the Constraints on the Hubble Constant
• Spectroscopy of Outlying H II Regions in Spiral Galaxies: Abundances and Radial Gradients
• On Measuring Chemical Abundances in Distant Galaxies Using Global Emission Line Spectra
• Where is the Neutral Atomic Gas in Hickson Groups?
• The Extreme Outer Regions of Disk Galaxies: I. Chemical Abundances of HII Regions
• The Formation of Dwarf Galaxies in Tidal Debris: A Study of the Compact Group Environment
• A Multiwavelength Study of Stephan's Quintet
• The Dwarf Irregular Galaxy UGC 7636 Exposed: Stripping At Work In The Virgo Cluster
• Kinematics and morphology of ionized gas in Hickson Compact Group 18
• ISO observations of Hickson Compact Group 31 with the central Wolf-Rayet galaxy NGC 1741

Cited by in corpus (12)

• Evidence for strong dynamical evolution in disk galaxies through the last 11 Gyr. GHASP VIII: A local reference sample of rotating disk galaxies for high redshift studies
• Probing the Dust Properties of Galaxies up to Submillimetre Wavelengths I. The Spectral Energy Distribution of dwarf galaxies using LABOCA
• The Origin of Faint Tidal Features Around Galaxies in the RESOLVE Survey
• Massive star formation in Wolf-Rayet galaxies: II. Optical spectroscopy results
• Massive star formation and tidal structures in HCG 31
• The K luminosity-metallicity relation for dwarf galaxies and the tidal dwarf galaxies in the tails of HCG 31
• Hierarchical Structure Formation and Modes of Star Formation in Hickson Compact Group 31
• The Compact Group of Galaxies HCG 31 is in an early phase of merging
• Diffuse X-ray-emitting Gas in Major Mergers
• Probing the nature of the pre-merging system Hickson Compact Group 31 through IFU data
• A MUSE view of the multiple interacting system HCG 31
• MeerKAT view of Hickson Compact Groups:I. Data description and release