Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A General Relativistic Null Hypothesis Test with Event Horizon Telescope
  Observations of the black-hole shadow in Sgr A*   The half opening angle of a Kerr black-hole shadow is always equal to
(5+-0.2)GM/Dc^2, where M is the mass of the black hole and D is its distance
from the Earth. Therefore, measuring the size of a shadow and verifying whether
it is within this 4% range constitutes a null hypothesis test of General
Relativity. We show that the black hole in the center of the Milky Way, Sgr A*,
is the optimal target for performing this test with upcoming observations using
the Event Horizon Telescope. We use the results of optical/IR monitoring of
stellar orbits to show that the mass-to-distance ratio for Sgr A* is already
known to an accuracy of +-4%. We investigate our prior knowledge of the
properties of the scattering screen between Sgr A and the Earth, the effects of
which will need to be corrected for in order for the black-hole shadow to
appear sharp against the background emission. Finally, we explore an edge
detection scheme for interferometric data and a pattern matching algorithm
based on the Hough/Radon transform and demonstrate that the shadow of the black
hole at 1.3 mm can be localized, in principle, to within ~9%. All these results
suggest that our prior knowledge of the properties of the black hole, of
scattering broadening, and of the accretion flow can only limit this General
Relativistic null hypothesis test with Event Horizon Telescope observations of
Sgr A* to 10%.

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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas