Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: BUDHIES I: characterizing the environments in and around two clusters at
  z~0.2   We present the optical spectroscopy for the Blind Ultra Deep HI Environmental
Survey (BUDHIES). With the Westerbork Synthesis Radio Telescope, BUDHIES has
detected HI in over 150 galaxies in and around two Abell clusters at z~0.2.
With the aim of characterizing the environments of the HI-detected galaxies, we
obtained multi-fiber spectroscopy with the William Herschel Telescope. In this
paper, we describe the spectroscopic observations, report redshifts and EW[OII]
measurements for ~600 galaxies, and perform an environmental analysis. In
particular, we present cluster velocity dispersion measurements for 5 clusters
and groups in the BUDHIES volume, as well as a detailed substructure analysis.

8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom