First of all, Elliptical galaxies are normally older and so have older stars, which are cooler and emit Yellow-Red light, Whereas spiral galaxies are typically older and emit more blue light.
Secondly, spiral galaxies have a bulge in the center that should be seen from the side, whereas eliptical galaxies are comparable to the spiral galaxies bulge, as it has no disc.
Thirdly, the distribution of velocities in an elliptical is much more random, so a measurement of red or blue shift should show differences between the two..
Hope this starts you off well..
Linear Mode
