PPT Slide
We therefore conclude that at least some massive cluster ellipticals have essentially finished their assembly by redshift 2.38. This is very consistent with all the evidence from lower redshifts for early formation of the stellar population of cluster ellipticals (as in Garth’s talk), though less comfortable for models like Guinivere Kauffmann’s, in which giant elliptical galaxies are hierarchically assembled rather later. Though it should be noted that B1 at least may well be an ongoing merger of two equal mass ellipticals. Their collision is only triggering around 1-10 solar masses per year of star formation (presumably due to the lack of gas in the two colliding components): this low rate would not significantly change the stellar population, preserving the fundamental plane.