Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lyman alpha emitters with red colors at z~=2.4   We have carried out a search for Lyman alpha emission from galaxies at z~=2.4
over a field of 1200 sq. arcmin using the CFH12K camera at the CFHT and a
custom medium band filter. The search has uncovered 58 candidates,
corresponding to a completeness-corrected source density of ~0.07 sq.
arcmin^-2. Our sources have red colors (B-I~=1.8) which imply either that a
large fraction of the light is highly reddened and we are detecting Lyman alpha
through special lines of sight, or that these objects contain an underlying
older stellar population. While for each individual object we cannot
discriminate between these alternatives, we conclude that most of the objects
actually contain an older component because the star formation rates inferred
from the picture based on reddening, applied to all candidates, would imply an
exceedingly high star formation rate, i.e. more than two orders of magnitude
above the peak cosmic star formation rate (e.g. Lilly et al. 1996).

10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th