The large asymmetric HI envelope of the isolated galaxy NGC 864 (CIG 96)

Abstract

We present a HI synthesis imaging study of NGC 864 (CIG 96), a spiral galaxy well isolated from similarly sized companions, yet presenting an intriguing asymmetry in its integral HI spectrum. The asymmetry in the HI profile is associated with a strong kinematical perturbation in the gaseous envelope of the galaxy, where at one side the decay of the rotation curve is faster than keplerian. We detect a small (M(HI) = 5 x 10^6 Msun) galaxy with a faint optical counterpart at around 80 kpc projected distance from NGC 864. This galaxy is probably not massive enough to have caused the perturbations in NGC 864. We discuss alternatives, such as the accretion of a gaseous companion at a radial velocity lower than the maximum.

arXiv comment4 pages, 7 figures; Astronomy & Astrophysics, in press; comments by the referee included

References in corpus (4)

• The Westerbork HI Survey of Spiral and Irregular Galaxies I. HI Imaging of Late-type Dwarf Galaxies
• Formation of rings in galactic discs by infalling small companions
• Numerical simulations of interacting gas-rich barred galaxies. Vertical impact of small companions
• Revised positions for the CIG galaxies

Cited by in corpus (16)

• The AMIGA sample of isolated galaxies. V. Quantification of the isolation
• The AMIGA sample of isolated galaxies: VIII. The rate of asymmetric HI profiles in spiral galaxies
• The AMIGA sample of isolated galaxies III. IRAS data and infrared diagnostics
• The AMIGA sample of isolated galaxies - II. Morphological refinement
• Absorption line-strengths of 18 late-type spiral galaxies observed with SAURON
• The AMIGA sample of isolated galaxies. IV. A catalogue of neighbours around isolated galaxies
• Star formation in isolated AMIGA galaxies: dynamical influence of bars
• Photometric characterization of a well defined sample of isolated galaxies in the context of the AMIGA project
• Hα Kinematics of S4G spiral galaxies-I. NGC 864
• Star formation in the extended gaseous disk of the isolated galaxy CIG 96
• A ~ 12 kpc HI extension and other HI asymmetries in the isolated galaxy CIG 340 (IC 2487)
• Diffuse HI Disks in Isolated Galaxies
• Unveiling the environment and faint features of the isolated galaxy CIG 96 with deep optical and HI observations
• HI asymmetry in the isolated galaxy CIG 85 (UGC 1547)
• Neutral atomic and molecular gas dynamics in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496
• HI asymmetries in the isolated galaxy CIG 292