Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-ray Reflection from Inhomogeneous Accretion Disks: I. Toy Models and
  Photon Bubbles   Numerical simulations of the interiors of radiation dominated accretion disks
show that significant density inhomogeneities can be generated in the gas.
Here, we present the first results of our study on X-ray reflection spectra
from such heterogeneous density structures. We consider two cases: first, we
produce a number of toy models where a sharp increase or decrease in density of
variable width is placed at different depths in a uniform slab. Comparing the
resulting reflection spectra to those from an unaltered slab shows that the
inhomogeneity can affect the emission features, in particular the Fe K and O
VIII Lyalpha lines. The magnitude of any differences depends on both the
parameters of the density change and the ionizing power of the illuminating
radiation, but the inhomogeneity is required to be within ~2 Thomson depths of
the surface to cause an effect. However, only relatively small variations in
density (on the order of a few) are necessary for significant changes in the
reflection features to be possible. Our second test was to compute reflection
spectra from the density structure predicted by a simulation of the non-linear
outcome of the photon bubble instability. The resulting spectra also exhibited
differences from the constant density models, caused primarily by a strong 6.7
keV iron line. Nevertheless, constant density models can provide a good fit to
simulated spectra, albeit with a low reflection fraction, between 2 and 10 keV.
Below 2 keV, differences in the predicted soft X-ray line emission result in
very poor fits with a constant density ionized disk model. The results indicate
that density inhomogeneities may further complicate the relationship between
the Fe K equivalent width and the X-ray continuum.

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The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: stat