Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The feature of shadow images and observed luminosity of the Bardeen
  black hole surrounded by different accretions   In this paper, by exploring the photon motion in the region near the Bardeen
black hole, the shadow and observation properties of the black hole surrounded
by various accretion models are studied. We analyzed the changes in shadow
imaging and observation luminosity when the relevant physical parameters are
changed. For the different spherical accretions background, one can find that
the radius of shadow and the position of photon sphere do not change, but the
observation intensity of shadow in the infalling accretion model is
significantly lower than that of the static case. When the black hole is
surrounded by an optically and thin disk accretion, the contribution of the
photon rings, lensing rings and direct emission to the total observed flux has
also been studied. Under the different forms of the emission modes, the result
shows that the observed brightness is mainly determined by direct emission,
while the lensing rings will provide a small part of the observation flux and
the photon ring can provide a negligible observation flux. By comparing our
results with the Schwarzschild spacetime, it is found that the existence or
change of relevant status parameters will greatly affect the shape and
observation intensity of black hole shadow. These results support that the
change of state parameter will affect the spacetime structure, thus affecting
the observation feature of black hole shadows.

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The categories of this paper are: quant-ph
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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: q-fin
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The categories of this paper are: econ
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The categories of this paper are: physics
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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: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
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The categories of this paper are: eess