Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Significantly off-center Ni56 Distribution for the Low-Luminosity Type
  Ia Supernova SN 2016brx from the 100IAS survey   We present nebular-phase spectra of the Type Ia supernova (SN Ia) 2016brx, a
member of the 1991bg-like subclass that lies at the faint end of the SN Ia
luminosity function. Nebular spectra are available for only three other
1991bg-like SNe, and their Co line centers are all within <~ 500 km/s of each
other. In contrast, the nebular Co line center of SN 2016brx is blue-shifted by
>1500 km/s compared to them and by ~1200 km/s compared to the rest frame. This
is a significant shift relative to the narrow nebular line velocity dispersion
of <~ 2000 km/s of these SNe. The large range of nebular line shifts implies
that the Ni56 in the ejecta of SN 1991bg-like events is off-center by ~1000
km/s rather than universally centrally confined as previously suggested. With
the addition of SN 2016brx, the Co nebular line shapes of 1991bg-like objects
appear to connect with the brighter SNe Ia that show double-peak profiles,
hinting at a continuous distribution of line profiles among SNe Ia. One class
of models to produce both off-center and bi-modal Ni56 distributions is
collisions of white dwarfs with unequal and equal masses.

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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph