Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Emission-Line Galaxies from the NICMOS/HST GRISM Parallel Survey   We present the first results of a survey of random fields with the slitless
G141 ($\lambda_c = 1.5\mu, \Delta\lambda=0.8\mu$) grism on NICMOS.
Approximately 64 square arcminutes have been observed at intermediate and high
galactic latitudes. The 3$\sigma$ limiting line and continuum fluxes in each
field vary from $7.5 \times 10^{-17}$ to $1 \times 10^{-17} erg/cm^2/sec$ and
from H = 20 to 22, respectively. Our median and area weighted $3\sigma $
limiting line fluxes within a 4 pixel aperture are nearly identical at $4.1
\times 10^{-17} erg/cm^2/sec$ and are 60% deeper than the deepest narrow-band
imaging surveys from the ground. We have identified 33 emission-line objects
and derive their observed wavelengths, fluxes and equivalent widths. We argue
that the most likely line identification is H$\alpha$ and that the redshift
range probed is from 0.75 to 1.9. The 2$\sigma$ rest-frame equivalent width
limits range from 9\AA to 130\AA with an average of 40\AA. The survey probes an
effective co-moving volume of $10^5 h_{50}^{-3} Mpc^3$ for $q_0=0.5$. Our
derived co-moving number density of emission line galaxies in the range $0.7 <
z < 1.9$ is $3.3\times10^{-4} h_{50}^{3} Mpc^{-3}$, very similar to that of the
bright Lyman break objects at $z \sim 3$. The objects with detected
emission-lines have a median F160W magnitude of 20.4 (Vega scale) and a median
H$\alpha$ luminosity of $2.7 \times 10^{42} erg/sec$. The implied star
formation rates range from 1 to 324 M_{\odot}/yr, with an average
[NII]6583,6548 corrected rate of 21 M_{\odot}/yr for H_0=50 km/s/Mpc and
$q_0=0.5$ (34 M_{\odot}/yr for $q_0=0.1$).

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The categories of this paper are: cs
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex