Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Compact Nuclei in Galaxies at Moderate Redshift: I. Imaging and
  Spectroscopy   This study explores the space density and properties of active galaxies to
z=0.8. We have investigated the frequency and nature of unresolved nuclei in
galaxies at moderate redshift as indicators of nuclear activity such as Active
Galactic Nuclei (AGN) or starbursts. Candidates are selected by fitting imaged
galaxies with multi-component models using maximum likelihood estimate
techniques to determine the best model fit. We select those galaxies requiring
an unresolved, point source component in the galaxy nucleus, in addition to a
disk and/or bulge component, to adequately model the galaxy light. We have
searched 70 WFPC2 images primarily from the Medium Deep Survey for galaxies
containing compact nuclei. In our survey of 1033 galaxies, the fraction
containing an unresolved nuclear component greater than 3% of the total galaxy
light is 16+/-3% corrected for incompleteness and 9+/-1% for nuclei greater
than 5% of the galaxy light. Spectroscopic redshifts have been obtained for 35
of our AGN/starburst candidates and photometric redshifts are estimated to an
accuracy of sigma_z=0.1 for the remaining sample. In this paper, the first of
two in this series, we present the selected HST imaged galaxies having
unresolved nuclei and discuss the selection procedure. We also present the
ground-based spectroscopy for these galaxies as well as the photometric
redshifts estimated for those galaxies without spectra.

12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an