Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The disappearance of the helium-giant progenitor of the type Ib
  supernova iPTF13bvn and constraints on its companion   We report and discuss post-explosion observations of supernova iPTF13bvn. We
find that the brightness of the SN at +740 days is below the level of the
pre-explosion source and thus confirm that the progenitor star has gone. We
estimate that the late-time brightness is still dominated by the supernova,
which constrains the magnitude and thus mass of a possible companion star to
below approximately 10Msun. In turn this implies that the progenitor's initial
mass is constrained to a narrow range of between 10 to 12Msun. The progenitor
of iPTF13bvn would have been a helium giant rather than a Wolf-Rayet star. In
addition, we suggest that sufficiently deep observations acquired in 2016 would
now stand a chance to directly observe the companion star.

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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc