Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The nature of the dwarf population in Abell 868   We present the results of a study of the morphology of the dwarf galaxy
population in Abell 868, a rich, intermediate redshift (z=0.154) cluster which
has a galaxy luminosity function with a steep faint-end slope (alpha=-1.26 +/-
0.05). A statistical background subtraction method is employed to study the B-R
colour distribution of the cluster galaxies. This distribution suggests that
the galaxies contributing to the faint-end of the measured cluster LF can be
split into three populations: dIrrs with B-R<1.4; dEs with 1.4<B-R<2.5; and
contaminating background giant ellipticals (gEs) with B-R>2.5. The remvoal of
the contribution of the background gEs from the counts only marginally lessens
the faint-end slope (alpha=-1.22 +/- 0.16). However, the removal of the
contribution of the dIrrs from the counts produces a flat LF (alpha=-0.91 +/-
0.16). The dEs and the dIrrs have similar spatial distributions within the
cluster except that the dIrrs appear to be totally absent within a central
projected radius of about 0.2 Mpc (Ho=75 km/s /Mpc). The number density of both
dEs and dIrrs appear to fall off beyond a projected radius of about 0.35 Mpc.
We suggest that the dE and dIrr populations of A868 have been associated with
the cluster for similar timescales but that evolutionary processes such as
`galaxy harassment' tend to fade the dIrr galaxies while having much less
effect on the dE galaxies. The harassement would be expected to have the
greatest effect on dwarfs residing in the central parts of the cluster.

17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
2
The categories of this paper are: math