Discovery of structure in the envelope of the cD galaxy in the cluster Abell 1795

We report the discovery of structure in the cD envelope of the central galaxy in the rich cluster A1795. The envelope extends predominantly in the north–south direction to at least 400 kpc from the centre of the galaxy. At the largest radii, there is a region to the south of low surface brightness that turns slightly to the east. The total I-band magnitude of the galaxy and envelope is at least – 26.6, indicating that it is one of the most luminous galaxies known. We suggest that the structure in the envelope has been caused by a past merger of the central galaxy with another giant galaxy, probably in a subcluster that merged with the cluster. This would explain the alignment of both cD envelope and cluster.