Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Studying the Nature of Dark Energy with Galaxy Clusters   We report on the status of our effort to constrain the nature of dark energy
through the evolution of the cluster mass function. Chandra temperature
profiles for 31 clusters from a local cluster sample are shown. The X-ray
appearance of the proto supermassive binary black hole at the center of the
cluster Abell 400 is described. Preliminary weak lensing results obtained with
Megacam@MMT for a redshift z=0.5 cluster from a distant cluster sample are
given.

9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga