Observations using the OASIS integral field spectrograph on the William Herschel Telescope have
revealed a long, thin plume of ionised gas stretching out from the
brightest cluster galaxy (BCG) of Abell 2146 (z=0.243) (Canning et al.
2012). Extended optical emission-line nebulae are not uncommon in the
cores of clusters, but the discovery of this particular structure is
unexpected, as the host cluster is in the throes of a major merger event.