1995/01/01 by Karl D. Rakos, K. D. Rakos, James M. Schombert
Environmental Science · Physics and Astronomy · #Remote Sensing in Agriculture #Impact of Light on Environment and Health #Astronomy and Astrophysical Research
paper · doi:10.1086/175150
Rest frame Stromgren photometry (3500 A, 4100 A, 4750 A, and 5500 A) is presented for 509 galaxies in 17 rich clusters between z = 0 and z = 1 as a test of color evolution. Our observations confirm a strong, rest frame, Butcher-Oemler effect where the fraction of blue galaxies increases from 20% at z = 0.4 to 80% at z = 0.9. We also find that a majority of these blue cluster galaxies are composed of normal disk or post-starburst systems based on color criteria. When comparing our colors to the morphological results from HST imaging, we propose that the blue cluster galaxies are a population of late-type, low surface brightness objects which fade and are then destroyed by the cluster tidal field. Alter isolating the red objects from Butcher-Oemler objects, we have compared the mean color of these old, non-star-forming objects with spectral energy distribution models in the literature as a test for passive galaxy evolution in ellipticals. We find good agreement with single-burst models which predict a mean epoch of galaxy formation at z = 5. Tracing the red envelope for ellipticals places the earliest epoch of galaxy formation at z = 10.