Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Determination of the properties of the central engine in microlensed
  QSOs   We study a recently observed gravitational microlensing peak in the V-band
light curve of Q2237+0305A using a relatively simple, but highly consistent
with the data (the best-fit reduced \chi^2 is very close to 1), physical model.
The source quasar is assumed to be a Newtonian geometrically-thin and
optically-thick accretion disk. The disk has an arbitrary orientation, and both
blackbody and greybody emission spectra are considered. When the
electron-photon scattering plays a role, the greybody spectrum will be a
simplified version of the exact one. In our model the microlensing variability
result from the source crossing a caustic straight line. The main goal is to
estimate the black hole mass and the mass accretion rate in QSO 2237+0305 as
well as to discuss the power and the weakness of the technique, some possible
improvements, and the future prospects from multifrequency monitoring of new
microlensing peaks. We also put into perspective the new methodology and the
results on the central engine in QSO 2237+0305. From the fitted microlensing
parameters and reasonable dynamical/cosmological constraints, it is concluded
that QSO 2237+0305 harbours a central massive black hole: 10^7 M_Sun < M < 6
10^8 M_Sun. While the information about the central dark mass is very
interesting, the mass accretion rate is not so well constrained. The typical
values of the disk luminosity/Eddington luminosity ratio are in the
(1-20)*\epsilon range, where \epsilon \leq 1 is the emissivity relative to a
blackbody and the highest L/L_{Edd} ratio corresponds to the largest deflector
motion. Therefore, in order to verify L/L_{Edd} \leq 1, a relatively small
projected peculiar motion of the lens galaxy and a greybody emission seem to be
favored.

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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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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: funct-an
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The categories of this paper are: plasm-ph