Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New active galactic nuclei detected in ROSAT All Sky Survey galaxies;
  Part I: Verification of selection strategy   We present the first results of a program to identify so far unknown active
nuclei (AGN) in galaxies. Candidate galactic nuclei have been selected for
optical spectroscopy from a cross-correlation of the ROSAT All Sky Survey
(RASS) bright source catalog with optical galaxy catalogs. A high X-ray flux
has been used as pointer to galaxies with a high probability to contain active
nuclei. Only galaxies have been accepted for the program for which no activity
was noted in NED. For many of the galaxies no radial velocity was reported
before. The optical spectra demonstrate that the galaxies cover a redshift
range of 0.014 to 0.13 and that most of them host active nuclei. For 75 percent
of the 33 candidates the X-ray emission is caused by the AGN. In addition
several of the remaining candidates host Seyfert 2/LINER nuclei that, however,
most certainly cannot explain the X-ray emission alone. Three BL Lac objects
have been detected serendipitously in galaxy fields that have been followed up
by short ROSAT HRI observations to confirm the X-ray galaxy identification with
improved position accuracy and point response function. The sources show X-ray
to radio flux ratios typical for X-ray selected BL Lac objects. The results
presented in the paper prove the selection strategy as very successful to
detect previously unknown AGN of all Seyfert 1 types in nearby galaxies
encouraging the extension of this program. The detection of new nearby AGN will
be used to initiate a detailed investigation of their multi-wavelength
properties and a comparison with the more distant AGN population.

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The categories of this paper are: stat
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
3
The categories of this paper are: physics