Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The X-ray variability and the near-IR to X-ray spectral energy
  distribution of four low luminosity Seyfert 1 galaxies   We present the results from a study of the X-ray variability and the near-IR
to X-ray spectral energy distribution of four low-luminosity, Seyfert 1
galaxies. We compared their variability amplitude and broad band spectrum with
those of more luminous AGN in order to investigate whether accretion in
low-luminosity AGN operates as in their luminous counterparts. We used archival
XMM-Newton and, in two cases, ASCA data to estimate their X-ray variability
amplitude and determine their X-ray spectral shape and luminosity. We also used
archival HST data to measure their optical nuclear luminosity, and near-IR
measurements from the literature, in order to construct their near-IR to X-ray
spectra. The X-ray variability amplitude of the four Seyferts is what one would
expect, given their black hole masses. Their near-IR to X-ray spectrum has the
same shape as the spectrum of quasars which are 10^2-10^5 times more luminous.
The objects in our sample are optically classified as Seyfert 1-1.5. This
implies that they host a relatively unobscured AGN-like nucleus. They are also
of low luminosity and accrete at a low rate. They are therefore good candidates
to detect radiation from an inefficient accretion process. However, our results
suggest that they are similar to AGN which are 10^2-10^5 times more luminous.
The combination of a "radiative efficient accretion disc plus an X-ray
producing hot corona" may persist at low accretion rates as well.

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The categories of this paper are: adap-org
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
18
The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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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: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys