Environmental effects on the structure of the dwarf spheroidal galaxies

The central surface brightness [mu(V)(0)] of the dwarf spheroidal satellites of our own Galaxy is found to correlate with their distance from the Galactic Centre (R(GC)). This observational evidence suggests that environmental effects could strongly influence their structure. This suggestion is further supported by a clear-cut bivariate correlation linking mu(V)(0) to a linear combination of M(V), the absolute integrated magnitude, and R(GC), which seems to be shared also by the M31 spheroidals. Possible implications for the Fundamental Plane of elliptical galaxies and dark matter (DM) content of dwarf spheroidals are also briefly discussed.