Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photometric Redshifts and Morphologies of Galaxies in the NICMOS
  Parallel Fields   We present positions, magnitudes, sizes and morphological classifications for
111 galaxies discovered in the Hubble Space Telescope NICMOS Camera 1 and
Camera 2 parallel fields. We combine the magnitudes measured in the JHK-analog
filters with those from deep ground-based images in V and/or R to measure
photometric redshifts for 71 objects using Bruzual-Charlot population synthesis
models. We find that these objects fall in the range z ~ 0.0 - 2.7, with a mean
redshift of 0.8 and a mean luminosity of 1.6 L*. The NICMOS images reveal many
of the objects to be ordered spirals and ellipticals similar to those in the
local universe. However, we find a higher fraction (~ 14%) of morphologically
peculiar and/or interacting galaxies than is observed among local galaxies (~
3% - 4%). This is consistent with the results from other deep HST images
including the Hubble Deep Field and Hubble Medium Deep Survey Field that the
fraction of peculiar and interacting galaxies increases with redshift. As the
NICMOS images of the sample galaxies cover their rest-frame near infrared and
optical emission, this result increases confidence that such changes in
morphology are genuine, as opposed to an effect produced by viewing galaxies in
the rest-frame ultraviolet. We also find that at least 26 of the sample
galaxies appear to be members of (non-interacting) pairs or groups, based on
their proximity to one another and photometric redshifts. This is consistent
with the results of recent ground-based optical surveys covering larger areas,
and with the detection of galaxy groups and filaments at redshifts higher than
those covered by our sample.

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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
3
The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: cs
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph