Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Studying the Evolution of Field Galaxies Using NICMOS/HST Parallel
  Imaging and Grism Data   We present results from our analysis of F160W NICMOS Parallel images. These
data cover $\sim$~9~sq. arcminutes and reach 3$\sigma$ depths of H$=$ 24.3 $-$
25.5 in a $0.6''$ diameter aperture with integration times of 2,000 to 13,000
seconds. We derive the first deep H band galaxy counts. The slope of the counts
for H$<$ 20 is 0.31, consistent with various K-band measurements from the Keck
telescopes. The measured number counts vs. magnitude relation is reasonably
well fitted with no-evolution models with a low $\Omega$ value. The half-light
radii of the galaxies declines steeply with apparent magnitude and reaches the
NIC3 resoltion limit at H$=$23.5. Deep ground-based VRI imaging of one NICMOS
field has revealed an extremely red galaxy with R$-$H $=$ 6 and H of 18.8. Our
analyses of the grism data show that we can reach 3$\sigma$ flux limits of of
$1\times 10^{-16}$ to $2\times10^{-17}$ ergs/sec/cm$^2$ for integration times
of 2,000 to 21,000~seconds. We have detected a total of 33 emission line
galaxies. The comoving number density is $\rm \sim 2\times 10^{-4} Mpc^{-3}$.
The detected emission lines are probably H$_\alpha$~6563\AA. Thus, the derived
star formation rates, without extinction correction, are $10 - 163 M\odot$ per
year for galaxies at redshifts between 0.7 and 1.9.

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The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: bayes-an