Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Star formation activity of intermediate redshift cluster galaxies out to
  the infall regions   We present a spectroscopic analysis of two galaxy clusters out to ~4Mpc at
z~0.2. The two clusters VMF73 and VMF74 identified by Vikhlinin et al. (1998)
were observed with MOSCA at the Calar Alto 3.5m telescope. Both clusters lie in
the ROSAT PSPC field R285 and were selected from the X-ray Dark Cluster Survey
(Gilbank et al. 2004) that provides optical V- and I-band data. VMF73 and VMF74
are located at respective redshifts of z=0.25 and z=0.18 with velocity
dispersions of 671 km/s and 442 km/s, respectively. The spectroscopic
observations reach out to ~2.5 virial radii. Line strength measurements of the
emission lines H_alpha and [OII]3727 are used to assess the star formation
activity of cluster galaxies which show radial and density dependences. The
mean and median of both line strength distributions as well as the fraction of
star forming galaxies increase with increasing clustercentric distance and
decreasing local galaxy density. Except for two galaxies with strong H_alpha
and [OII] emission, all of the cluster galaxies are normal star forming or
passive galaxies. Our results are consistent with other studies that show the
truncation in star formation occurs far from the cluster centre.

14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin