The Transformation of Cluster Galaxies at Intermediate Redshift
Ford, H. C.; Demarco, R.; Infante, L.; Zheng, W.; Feldman, P. D.; Menanteau, F.; Rosati, P.; Jee, M. J.; Bouwens, R. J.; Illingworth, G. D.; Blakeslee, J. P.; Broadhurst, T. J.; Franx, M.; Sparks, W. B.; Goto, T.; Mei, S.; Miley, G. K.; Postman, M.; Benítez, N.; Ardila, D. R.; Kimble, R. A.; Clampin, M.; Golimowski, D. A.; Cross, N. J. G.; Holden, B.; Bradley, L. D.; Zirm, A.; Gronwall, C.; Martel, A. R.; White, R. L.; Tran, H. D.; Sirianni, M.; Bartko, F.; Meurer, G. R.; Motta, V.; Brown, R. A.; Homeier, N. L.; Hartig, G. F.; Burrows, C. J.; Cheng, E. S.; Krist, J. E.; Lesser, M. P.; Tsvetanov, Z. I.
United States, Germany, Netherlands, Jerusalem, Chile
Abstract
We combine imaging data from the Advanced Camera for Surveys (ACS) with VLT/FORS optical spectroscopy to study the properties of star-forming galaxies in the z=0.837 cluster Cl 0152-1357. We have morphological information for 24 star-forming cluster galaxies, which range in morphology from late-type and irregular to compact early-type galaxies. We find that while most star-forming galaxies have r625-i775 colors bluer than 1.0, eight are in the red cluster sequence. Among the star-forming cluster population, we find five compact early-type galaxies that have properties consistent with their identification as progenitors of dwarf elliptical galaxies. The spatial distribution of the star-forming cluster members is nonuniform. We find none within R~500 Mpc of the cluster center, which is highly suggestive of an intracluster medium interaction. We derive star formation rates from [O II] λ3727 line fluxes and use these to compare the global star formation rate of Cl 0152-1357 to other clusters at low and intermediate redshifts. We find a tentative correlation between integrated star formation rates and TX, in the sense that hotter clusters have lower integrated star formation rates. Additional data from clusters with low X-ray temperatures are needed to confirm this trend. We do not find a significant correlation with redshift, suggesting that evolution is either weak or absent between z=0.2 and 0.8.
Based on observations carried out at the ESO Very Large Telescope (VLT), Chile, as part of the ESO Large Program LP-166.A-0701 and proposals 69.A-0683 and 72.A-0759.