Conclusions

HI observations of the LGG 138 galaxy group have revealed a kpc diameter ring of gas projected around two bright spiral galaxies in the group. The ring exhibits regular rotation, and future numerical models may show it to be additionally undergoing expansion or contraction. Deep optical images show a break in stellar colour associated with the southern and south western parts of the ring. The ring is most likely to have formed either from the tidal accretion of gas from the nearby galaxy NGC 2295, or instead during the perturbed collapse of one of NGC 2292/2293, probably the latter. Future studies will be directed at re-measuring the radial velocities of the galaxies NGC 2292/2293/2295, possibly mapping the rotation of the galaxy nuclei, and searching for CO emission in NGC 2295 to ascertain whether it is likely to have lost HI gas to the NGC 2292/2293 pair.

© Copyright Astronomical Society of Australia 1997