Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical Surveys for Galaxy Clusters   We present a brief review of the history of optical searches of galaxy
clusters, starting from that of Abell. The traditional application of this
survey method suffers from contamination due to projection of galaxies along
the line of sight, which becomes increasingly more severe at higher redshift.
The new generation of wide-field CCD imagers has provided a renewed impetus for
optical surveys for clusters. We describe a new cluster finding technique using
the red sequence of early-type galaxies in galaxy groups and clusters, which
eliminates the projection problem by essentially producing a 3-D distribution
of red galaxies using two-filter imaging data. The Red-Sequence Cluster Survey
(RCS) is a 100 square degree optical survey, carried out using 4m class
telescopes, which is optimally designed to search for clusters at $0.5<z<1.4$\
utilizing this technique. We present preliminary results which indicate that
the RCS is extremely efficient in detecting galaxy clusters at these redshifts,
including a number of clusters with multiple strong lensing arcs.

22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc