The Colour-Magnitude Relation for Elliptical Galaxies

Aims of the Experiment

  1. To introduce galaxy morphology.
  2. To discuss the formation of galaxy clusters.
  3. To illustrate the measurement of colours and magnitudes of galaxies.
  4. To map the relationship between magnitude and colour for galaxies in a rich cluster.
  5. To compare the colours of elliptical galaxies in nearby and distant clusters. Then to use the bluing of the distant galaxies, along with the known colour evolution of stellar populations as a function of time, to estimate the lookback time to the distant cluster.

Links to exercise

This is a modified version of an exercise, originally designed by Dr. Ian Smail, (Department of Physics, University of Durham). The modified version was made by Erik Zackrisson (Department of Astronomy and Space Physics, Uppsala University). Current version valid for course on Galaxies and Cosmology given at Stockholm Observatory, Stockholm University.