The image above shows the combination of a UKIRT/UFTI image and an HST image (taken in the K- and I-bands, respectively) of the brightest cluster galaxy in Abell 193. The UKIRT image reveals 3 nuclei in this galaxy for the first time, demonstrating the excellent spatial resolution available with UKIRT (FWHM~0.35"). This is only a factor of ~2 worse than the resolution capabilities of HST in the I band!

Galaxies such as this one are thought to be constantly growing at the centres of clusters as they "cannibalise" their less massive neighbours. As a result, multiple nuclei are seen in approximately 50% of the brightest cluster galaxies. In this galaxy (IC 1695) the combined UKIRT and HST data demonstrate that - if the cannibalism hypothesis is true - a merger has taken place in its recent history.

Our thanks to Marc Seigar (JAC) for supplying the data and text for this Gallery article.