Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The accretion mechanism in low-power radio galaxies   We study a sample of 44 low-luminosity radio-loud AGN, which represent a
range of nuclear radio-power spanning 5 orders of magnitude, to unveil the
accretion mechanism in these galaxies. We estimate the accretion rate of gas
associated with their hot coronae by analyzing archival Chandra data, to derive
the deprojected density and temperature profiles in a spherical approximation.
Measuring the jet power from the nuclear radio-luminosity, we find that the
accretion power correlates linearly with the jet power, with an efficiency of
conversion from rest mass into jet power of ~0.012. These results strengthen
and extend the validity of the results obtained by Allen and collaborators for
9 radio galaxies, indicating that hot gas accretion is the dominant process in
FR I radio galaxies across their full range of radio-luminosity.
  We find that the different levels of nuclear activity are driven by global
differences in the structure of the galactic hot coronae. A linear relation
links the jet power with the host X-ray surface brightness. This implies that a
substantial change in the jet power must be accompanied by a global change in
its ISM properties, driven for example by a major merger. This correlation
provides a simple widely applicable method to estimate the jet-power of a given
object by observing the intensity of its host X-ray emission.
  To maintain the mass flow in the jet, the fraction of gas that crosses the
Bondi radius reaching the accretion disk must be > 0.002. This implies that the
radiative efficiency of the disk must be < 0.005, an indication that accretion
in these objects occurs not only at a lower rate, but also at lower efficiency
than in standard accretion disks.

31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an