Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Substructure in dark matter halos: Towards a model of the abundance and
  spatial distribution of subclumps   I develop a model for the abundance and spatial distribution of dark matter
subclumps. The model shows that subclumps of massive parent halos formed at
earlier times than subclumps of the same mass in lower mass parents;
equivalently, halos in dense regions at a given time formed earlier than halos
of the same mass in less dense regions. This may provide the basis for
interpreting recent observations which indicate that the stellar populations of
the most massive elliptical galaxies are also the oldest.

31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat