Clusters at half hubble time: galaxy structure and colors in rx j0152.7-1357 and ms 1054-03
Mar, 200630 pages
Published in:
- Astrophys.J. 644 (2006) 30-53
e-Print:
- astro-ph/0603058 [astro-ph]
DOI:
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Abstract: (arXiv)
We study the photometric and structural properties of spectroscopically confirmed members in the two massive X-ray--selected z=0.83 galaxy clusters MS1054-03 and RXJ0152-1357 using three-band mosaic imaging with the Hubble Space Telescope Advanced Camera for Surveys. The samples include 105 and 140 members of MS1054-03 and RXJ0152-1357, respectively, with ACS F775W magnitude < 24.0. We develop a promising new structural classification method, based on a combination of the best-fit Sersic indices and the normalized root-mean-square residuals from the fits: the resulting classes agree well with the visual ones, but are less affected by galaxy orientation. We examine the color--magnitude relations in detail and find that the color residuals correlate with the local mass density measured from our weak lensing maps: we identify a threshold density of , in units of the critical density, above which the star formation appears to cease. For RXJ0152-1357, we also find a trend in the color residuals with velocity, resulting from an offset of about 980 km/s in the mean redshifts of the early- and late-type galaxies. Analysis of the color--color diagrams indicates that a range of star formation time-scales are needed to reproduce the loci of the galaxy colors. We also identify some cluster galaxies whose colors can only be explained by large amounts, mag, of internal dust extinction. [Abstract shortened]- cosmology: observations
- galaxies: clusters: individual (MS 1054-0321, RX J0152.7-1357)
- galaxies: elliptical and lenticular, cD
- galaxies: evolution
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