Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A VLT/FORS2 spectroscopic survey in the HDF-S   We report on low-resolution multi-object spectroscopy of 65 objects from
I(AB) ~= 20 to I(AB) ~= 25 in the HDF-S obtained with the VLT Focal Reducer/low
dispersion Spectrograph (FORS2). 18 objects belong to the HDF-S proper, i.e.
the WFPC2 deep area. 15 high-redshift galaxies with 2.0 < z < 3.5 (10 in the
HDF-S proper) have been identified. The spectroscopic redshifts are in good
agreement with the photometric ones derived from a chi^{2} minimization
technique comparing the observed spectral energy distribution with synthetic
libraries and with a new neural network (NN) approach. The dispersion with the
former method is sigma_z=0.16 whereas the latter provides sigma_z=0.13. No
"catastrophic" difference is encountered. The inferred star formation rates of
the individual objects range from tens to a few hundreds of M_{\odot} yr^{-1}
and the global star formation rate of the Universe at <z>=~2.4 is estimated to
be 0.15 M_{\odot} yr^{-1} Mpc^{-3} with a statistical error of 0.04. Evidence
for large scale structure is found with two groups' redshifts observed at z ~=
2.1 and z ~= 2.7 and a pronounced low redshift peak around z ~= 0.58. An
elliptical galaxy lensing a background object turns out to be at a redshift
z=0.577.

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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: math
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th