Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mass Outflow from the Nucleus of the Seyfert 1 Galaxy NGC 4151   We present an analysis of UV and optical spectra of NGC 4151 obtained at high
spectral and angular resolutions with the Hubble Space Telescope's (HST's)
Space Telescope Imaging Spectrograph (STIS). We identify a kinematic component
of the emission lines that has a width of 1170 km/s (FWHM), intermediate
between those from the broad and narrow (emission) line regions (BLR and NLR).
We present evidence that these emission lines arise from the same gas
responsible for most of the high-column UV and X-ray absorption (component
``D+E'') that we see in outflow at a distance of ~0.1 pc from the central
nucleus. The gas in this intermediate-line region (ILR) shields the NLR and has
a global covering factor of ~0.4, based on the observed C IV fluxes, indicating
mass outflow over a large solid angle centered on the accretion disk's axis. A
large transverse velocity (> 2100$ km/s) compared to the radial velocity
centroid (-490$ km/s) indicates that the kinematics is dominated by rotation at
this distance, but has a significant outflow component. The mass outflow rate
at 0.1 pc is ~0.16 solar masses/yr, which is about 10 times the accretion rate.
Based on physical conditions in the gas and dynamical considerations, models
that invoke magnetocentrifugal acceleration (e.g., in an accretion-disk wind)
are favored over those that rely on radiation driving or thermal expansion as
the principal driving mechanism for the mass outflow.

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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th