We present the results of a Keck- esi study of dwarf galaxies across a range of environment : the Perseus Cluster , the Virgo Cluster , the NGC 1407 group , and the NGC 1023 group .
Eighteen dEs are targeted for spectroscopy , three for the first time .
We confirm cluster membership for one Virgo dE , and group membership for one dE in the NGC 1023 group , and one dE in the NGC 1407 group for the first time .
Regardless of environment , the dEs follow the same size-magnitude and \sigma -luminosity relation .
Two of the Virgo dwarfs , VCC 1199 and VCC 1627 , have among the highest central velocity dispersions ( \sigma _ { 0 } = 58.4 km s ^ { -1 } and 49.2 km s ^ { -1 } ) measured for dwarfs of their luminosity ( M _ { R } \approx - 17 ) .
Given their small sizes ( R _ { e } < 300 pc ) and large central velocity dispersions , we classify these two dwarfs as compact ellipticals rather than dEs .
Group dEs typically have higher mean dynamical-to-stellar mass ratios than the cluster dEs , with M _ { dyn } / M _ { \star } = 5.1 \pm 0.6 for the group dwarfs , vs . M _ { dyn } / M _ { \star } = 2.2 \pm 0.5 for the cluster sample , which includes two cEs .
We also search for trends in M _ { dyn } / M _ { \star } vs. distance from M87 for the Virgo Cluster population , and find no preference for dwarfs with high values of M _ { dyn } / M _ { \star } to reside in the cluster outskirts vs. centre .