Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Main Epoch of Metal Production in the Universe   Clusters of galaxies allow a direct estimate of the metallicity and metal
production yield on the largest scale so far. It is argued that cluster
metallicity (about 1/3 solar) should be taken as representative of the low-z
universe as a whole. There is now compelling evidence that the bulk of stars
not only in cluster ellipticals but also in field ellipticals and bulges formed
at high redshifts (z>~ 3). Since such stars account for at least 30% of the
baryons now locked into stars, it is argued that at least 30% of stars and
metals formed before z=~3, and correspondingly the metallicity of the universe
at z=3 is predicted to be about 1/10 solar.

30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas