Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Combined VLBI- and X-ray Observations of Active Galactic Nuclei   Compact radio cores in radio-loud active galactic nuclei (AGNs) are classical
targets of Very-Long-Baseline interferometric (VLBI) research. Until today
little has been known about their X-ray properties in comparison to radio-quiet
AGNs. Here, we present results from a systematic X-ray spectral survey of
radio-loud AGNs. This study is based on a statistically complete sample of
regularly monitored compact, extragalactic radio jets from the VLBA 2 cm Survey
and makes use of high-quality X-ray spectroscopic data from the archives of the
X-ray observatories ASCA, BeppoSax, CHANDRA, and XMM-Newton. Combined VLBI and
X-ray observations of AGNs can yield direct observational links between the
central parsecs of extragalactic jets and dynamical processes within the
accretion flows around supermassive black holes. It is essential to establish
such links, which might have the power to attack the unsolved problem: "What
makes an AGN radio-loud?" We present some early results from our survey project
and report briefly on detailed studies of 0716+714, NGC 1052, and 3C 390.3.

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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol