Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hybrid nature of 0846+51W1: a BL Lac object with a narrow line Seyfert 1
  nucleus   We have found a NLS1 nucleus in the extensively studied eruptive BL Lac,
0846+51W1, out of a large sample of NLS1 compiled from the spectroscopic
dataset of SDSS DR1. Its optical spectrum can be well decomposed into three
components, a power law component from the relativistic jet, a stellar
component from the host galaxy, and a component from a typical NLS1 nucleus.
The emission line properties of 0846+51W1, FWHM(Hbeta) ~ 1710 km s^-1 and
[OIII]5007/Hbeta ~ 0.32 when it was in faint state, fulfil the conventional
definition of NLS1. Strong FeII emission is detected in the SDSS spectrum,
which is also typical of NLS1s. We try to estimate its central black hole mass
using various techniques and find that 0846+51W1 is very likely emitting at a
few times 10% L_Edd. We speculate that Seyfert-like nuclei, including NLS1s,
might be concealed in a significant fraction of BL Lacs but have not been
sufficiently explored due to the fact that, by definition, the optical-UV
continuum of such kind of objects are often overwhelmed by the synchrotron
emission.

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The categories of this paper are: acc-phys
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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: hep-ph
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The categories of this paper are: math
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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: nlin
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The categories of this paper are: funct-an
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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: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: physics
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The categories of this paper are: stat