Optical Signatures of High-Redshift Galaxy Clusters
Abstract
We combine an N-body and gasdynamic simulation of structure formation with an updated population synthesis code to explore the expected optical characteristics of a high-redshift cluster of galaxies. We examine a poor (2 keV) cluster formed in a biased, cold dark matter cosmology and employ simple, but plausible, threshold criteria to convert gas into stars. At z = 2, the forming cluster appears as a linear chain of very blue (g - r~0) galaxies, with 15 objects brighter than r = 25 within a 1 square arcmin field of view. After 2 Gyr of evolution, the cluster viewed at z = 1 displays both freshly infalling blue galaxies and red galaxies robbed of recent accretion by interaction with the hot intracluster medium. The range in G - R colors is ~3 mag at z = 1, with the reddest objects lying at sites of highest galaxy density. We suggest that red, high-redshift galaxies lie in the cores of forming clusters and that their existence indicates the presence of a hot intracluster medium at redshifts z~2. The simulated cluster viewed at z = 2 has several characteristics similar to the collection of faint, blue objects identified by Dressler et al. in a deep Hubble Space Telescope observation. The similarities provide some support for the interpretation of this collection as a high- redshift cluster of galaxies.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1994
- DOI:
- 10.1086/187263
- Bibcode:
- 1994ApJ...424L..13E
- Keywords:
-
- Dark Matter;
- Dissipation;
- Elliptical Galaxies;
- Gas Dynamics;
- Halos;
- Images;
- Star Formation;
- Stellar Evolution;
- Hubble Space Telescope;
- Line Of Sight;
- Metallicity;
- Rosat Mission;
- Space Density;
- Stellar Magnitude;
- Wavelengths;
- Astrophysics;
- COSMOLOGY: THEORY;
- GALAXIES: CLUSTERS OF;
- GALAXIES: EVOLUTION;
- GALAXIES: FORMATION