Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A sample of radio galaxies spanning three decades in radio luminosity -
  I. The host-galaxy properties and black-hole masses   The results of analysis of HST I-band imaging of a sample of 41 radio
galaxies spanning three orders of magnitude in radio luminosity at redshift
z~0.5 are presented. The full sample is drawn from four complete, low-frequency
selected radio samples with progressively fainter flux-density limits (3CRR,
6CE, 7CRS and the new TexOx-1000 sample). Modelling of the HST imaging data
shows that the host galaxies have surface-brightness distributions consistent
with those expected for classic ellipticals (Sersic parameter, beta~0.25), with
beta in the range 0.17<beta<0.30, and a mean of <beta>=0.23\pm0.01. The
host-galaxy luminosities are comparable with those of galaxies drawn from the
bright end of the local cluster galaxy luminosity function, spanning the range
0.7L^{\star}<L<10L^{\star}, with a mean of 3.2\pm0.3 L^{\star}. In addition,
the radio galaxies are shown to follow a Kormendy relation indistinguishable
from that of powerful low-redshift radio galaxies. Combining our new results
with those in the literature it is found that the scalelengths and Kormendy
relations of 3C-class radio galaxies do not vary significantly over the
redshift range 0.0<z<0.8, providing no evidence for dynamical evolution of this
class of host galaxy within this redshift interval. Converting the host-galaxy
luminosities into black-hole mass estimates predicts that the radio galaxies
harbour central black holes with masses in the range 10^{8.1}\Msun <M_{bh}<
10^{9.5}\Msun, with a geometric mean of <M_{bh}>=10^{8.87\pm 0.04}\Msun.
Finally, a significant (~3 sigma) correlation is found between black-hole mass
and 151-MHz radio luminosity for those objects in the sample with either
high-excitation nuclear spectra or classical double radio structures.
(abridged)

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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex