Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gamma-ray lines from SN2014J   On 21 January 2014, SN2014J was discovered in M82 and found to be the closest
type Ia supernova (SN Ia) in the last four decades. INTEGRAL observed SN2014J
from the end of January until late June for a total exposure time of about 7
Ms. SNe Ia light curves are understood to be powered by the radioactive decay
of iron peak elements of which $^{56}$Ni is dominantly synthesized during the
thermonuclear disruption of a CO white dwarf (WD). The measurement of
$\gamma$-ray lines from the decay chain
$^{56}$Ni$\rightarrow$$^{56}$Co$\rightarrow$$^{56}$Fe provides unique
information about the explosion in supernovae. Canonical models assume
$^{56}$Ni buried deeply in the supernova cloud, absorbing most of the early
$\gamma$-rays, and only the consecutive decay of $^{56}$Co should become
directly observable through the overlaying material several weeks after the
explosion when the supernova envelope dilutes as it expands. Surprisingly, with
the spectrometer on INTEGRAL, SPI, we detected $^{56}$Ni $\gamma$-ray lines at
158 and 812 keV at early times with flux levels corresponding to roughly 10% of
the total expected amount of $^{56}$Ni, and at relatively small velocities.
This implies some mechanism to create a major amout of $^{56}$Ni at the
outskirts, and at the same time to break the spherical symmetry of the
supernova. One plausible explanation would be a belt accreted from a He
companion star, exploding, and triggering the explosion of the white dwarf. The
full set of observations of SN2014J show $^{56}$Co $\gamma$-ray lines at 847
and 1238 keV, and we determine for the first time a SN Ia $\gamma$-ray light
curve. The irregular appearance of these $\gamma$-ray lines allows deeper
insights about the explosion morphology from its temporal evolution and
provides additional evidence for an asymmetric explosion, from our
high-resolution spectroscopy and comparisons with recent models.

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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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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: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org