Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-01-16
Astrophys.J. 639 (2006) 81-94
Astronomy and Astrophysics
Astrophysics
ApJ, in press
Scientific paper
10.1086/499259
The color-magnitude relation has been determined for the RDCS J0910+5422 cluster of galaxies at redshift z = 1.106. Cluster members were selected from HST ACS images, combined with ground--based near--IR imaging and optical spectroscopy. The observed early--type color--magnitude relation (CMR) in (i_775 -z_850) versus z_850 shows intrinsic scatters in color of 0.042 +/- 0.010 mag and 0.044 +/- 0.020 mag for ellipticals and S0s, respectively. From the scatter about the CMR, a mean luminosity--weighted age t > 3.3 Gyr (z > 3) is derived for the elliptical galaxies. Strikingly, the S0 galaxies in RDCS J0910+5422 are systematically bluer in (i_775 - z_850) by 0.07 +/- 0.02 mag, with respect to the ellipticals. The ellipticity distribution as a function of color indicates that the face-on S0s in this particular cluster have likely been classified as elliptical. Thus, if anything, the offset in color between the elliptical and S0 populations may be even more significant. The color offset between S0 and E corresponds to an age difference of ~1 Gyr, for a single-burst solar metallicity model. A solar metallicity model with an exponential decay in star formation will reproduce the offset for an age of 3.5 Gyr, i.e. the S0s have evolved gradually from star forming progenitors. The early--type population in this cluster appears to be still forming. The blue early-type disk galaxies in RDCS J0910+5422 likely represent the direct progenitors of the more evolved S0s that follow the same red sequence as ellipticals in other clusters. Thirteen red galaxy pairs are observed and the galaxies associated in pairs constitute ~40% of the CMR galaxies in this cluster.
Blakeslee John P.
Bouwens Rychard J.
Clampin Marc
Demarco Ricardo
Eisenhardt Peter
No associations
LandOfFree
Evolution of the Color-Magnitude Relation in High-Redshift Clusters: Blue Early-Type Galaxies and Red Pairs in RDCS J0910+5422 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Evolution of the Color-Magnitude Relation in High-Redshift Clusters: Blue Early-Type Galaxies and Red Pairs in RDCS J0910+5422, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evolution of the Color-Magnitude Relation in High-Redshift Clusters: Blue Early-Type Galaxies and Red Pairs in RDCS J0910+5422 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-523664