Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the origin of short GRBs with Extended Emission and long GRBs without
  associated SN   The Burst and Transient Source Experiment (BATSE) classifies cosmological
gamma-ray bursts (GRBs) into short (less than 2 s) and long (over 2 s) events,
commonly attributed to mergers of compact objects and, respectively, peculiar
core-collapse supernovae. This standard classification has recently been
challenged by the {\em Swift} discovery of short GRBs showing Extended Emission
(SGRBEE) and nearby long GRBs without an accompanying supernova (LGRBN). Both
show an initial hard pulse, characteristic of SGRBs, followed by a long
duration soft tail. We here consider the spectral peak energy
($E_{p,i}$)-radiated energy $(E_{iso})$ correlation and the redshift
distributions to probe the astronomical and physical origin of these different
classes of GRBs. We consider {\em Swift} events of $15$ SGRBs, $7$ SGRBEEs, 3
LGRBNs and 230 LGRBs. The spectral-energy properties of the initial pulse of
both SGRBEE and LGRBNs are found to coincide with those of SGRBs. A Monte Carlo
simulation shows that the redshift distributions of SGRBs, SGRBEE and LGRBNs
fall outside the distribution of LGRBs at 4.75$\,\sigma$, 4.67$\,\sigma$ and
4.31$\sigma$, respectively. A distinct origin of SGRBEEs with respect to LGRBs
is also supported by the elliptical host galaxies of the SGRBEE events 050509B
and 050724. This combined evidence supports the hypothesis that SGRBEE and
LGRBNs originate in mergers as SGRBs. Moreover, long/soft tail of SGRB and
LGRBNs satisfy the same $E_{p,i}-E_{iso}$ Amati-correlation holding for normal
LGRBs. This fact points to rapidly rotating black holes as a common long-lived
inner engine produced by different astronomical progenitors (mergers and
supernovae).

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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom