Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical observations of the fast declining type Ib supernova iPTF13bvn   We present optical UBVRI photometry and medium resolution spectroscopy of the
type Ib supernova iPTF13bvn, spanning a phase of $\sim$ $-13\,$d to $+71\,$d
with respect to $B$-band maximum. The post maximum decline rates indicate a
fast decline with $\Delta m_{15}(B) = 1.82$. Correcting for a galactic
extinction $E(B-V){\rm_{MW}}=0.045$ and host galaxy extinction of
$E(B-V){\rm_{host}}=0.17$, the absolute $V$-band magnitude peaks at
M$_V=-17.23\, \pm \,0.20$. The bolometric light curve indicates that $\sim
0.09$ M$_{\odot}$ of $^{56}$Ni was synthesized in the explosion. The earliest
spectrum ($-13$d) shows the presence of He~{\sc i} 5876 \AA\ feature at a
velocity of $\sim$15000 km s$^{-1}$, which falls rapidly by the time the SN
approaches the epoch of B-band maximum. The photospheric velocity near maximum
light, as indicated by the Fe~{\sc ii} 5169~\AA\ feature, is $\sim 9000$ km
s$^{-1}$. The estimate for the $^{56}$Ni mass, together with the estimates for
the ejected mass ($M_{\rm{ej}}$) and kinetic energy of the explosion
($E_{\rm{k}}$) indicate that iPTF13bvn is a low luminosity type Ib supernova,
with a lower than average ejected mass and kinetic energy. Our results suggest
that the progenitor of iPTF13bvn is inconsistent with a single Wolf-Rayet star.

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The categories of this paper are: stat
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex