We present the results of a Keck- esi spectroscopic study of six dwarf elliptical ( dE ) galaxies in the Perseus Cluster core , and confirm two dwarfs as cluster members for the first time .
All six dEs follow the size-magnitude relation for dE/dSph galaxies .
Central velocity dispersions are measured for three Perseus dwarfs in our sample , and all lie on the \sigma -luminosity relation for early-type , pressure supported systems .
We furthermore examine SA 0426-002 , a unique dE in our sample with a bar-like morphology surrounded by low-surface brightness wings/lobes ( \mu _ { B } = 27 mag arcsec ^ { -2 } ) .
Given its morphology , velocity dispersion ( \sigma _ { 0 } = 33.9 \pm 6.1 km s ^ { -1 } ) , velocity relative to the brightest cluster galaxy NGC 1275 ( 2711 km s ^ { -1 } ) , size ( R _ { e } = 2.1 \pm 0.10 kpc ) , and Sérsic index ( n = 1.2 \pm 0.02 ) , we hypothesise the dwarf has morphologically transformed from a low mass disc to dE via harassment .
The low-surface brightness lobes can be explained as a ring feature , with the bar formation triggered by tidal interactions via speed encounters with Perseus Cluster members .
Alongside spiral structure found in dEs in Fornax and Virgo , SA 0426-002 provides crucial evidence that a fraction of bright dEs have a disc infall origin , and are not part of the primordial cluster population .