1. Galaxy Clusters and the Butcher-OemlerEffect:
Galaxy Transformation by Environment
Emily Cross and Kristine Salters

2. “Like cities, each cluster has
unique characteristics and
population demographics:
Coma, Virgo, and the Local
Group are as different from
each other as
Toronto, Bangkok, and Rio de
Janeiro” (S&T: January 1988, page 16).

3. Galaxy cluster with high redshift have a

higher blue star forming spiral population
Low redshift, low blue spiral population


6. RED SHIFT

7. Infalling spiral galaxy
Galaxy cluster

8. Merging

Starburst

The youths
Ram pressure stripping

Tidal disruption

SF completely exhausted

9. We had never seen the phase between the

young blue spirals and the old red ellipticals
until November
of 2008

10. Photo


11. The evolving properties of
galaxies in clusters offer a unique
opportunity to connect evolution
on scales ranging from individual
galaxies to overall cosmic
evolution