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| Paper: |
A Keck Spectroscopic Study of MS 1054–03 (z = 0.83): Forming the Red Sequence |
| Volume: |
379, Cosmic Frontiers |
| Page: |
348 |
| Authors: |
Tran, K.-V.H. |
| Abstract: |
Using a magnitude-limited, spectroscopic survey of the X-ray luminous galaxy cluster MS 1054–03, we isolate 153 cluster galaxies and measure MS1054’s redshift and velocity dispersion to be z = 0.8307 ± 0.0004 and σz = 1156 ± 82 km s−1. The absorption-line, post-starburst (“E+A”), and emission-line galaxies respectively make up 63±7%, 15±4%, and 23±4% of the cluster population. With photometry from HST/ACS, we find that the absorption-line members define an exceptionally tight red sequence over a span of ~ 3.5 magnitudes in i775: their intrinsic scatter in (V606 − i775) color is only 0.048 ± 0.008, corresponding to a (U − B)z scatter of 0.041. Their color scatter is comparable to that of the ellipticals (σV i = 0.055 ± 0.008), but measurably smaller than that of the combined E+S0 sample (σV i = 0.072 ± 0.010). The color scatter of MS1054’s absorption-line population is approximately twice that of the ellipticals in Coma; this difference is consistent with passive evolution where most of the absorption-line members (> 75%) formed by z ~ 2, and all of them by z ~ 1.2. |
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