Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultra-bright optical transients are linked with type Ic supernovae   Recent searches by unbiased, wide-field surveys have uncovered a group of
extremely luminous optical transients. The initial discoveries of SN 2005ap by
the Texas Supernova Search and SCP-06F6 in a deep Hubble pencil beam survey
were followed by the Palomar Transient Factory confirmation of host redshifts
for other similar transients. The transients share the common properties of
high optical luminosities (peak magnitudes ~ -21 to -23), blue colors, and a
lack of H or He spectral features. The physical mechanism that produces the
luminosity is uncertain, with suggestions ranging from jet-driven explosion to
pulsational pair-instability. Here we report the most detailed photometric and
spectral coverage of an ultra-bright transient (SN 2010gx) detected in the
Pan-STARRS 1 sky survey. In common with other transients in this family,
early-time spectra show a blue continuum, and prominent broad absorption lines
of O II. However, about 25d after discovery, the spectra developed type Ic
supernova features, showing the characteristic broad Fe II and Si II absorption
lines. Detailed, post-maximum follow-up may show that all SN 2005ap and
SCP-06F6 type transients are linked to supernovae Ic. This poses problems in
understanding the physics of the explosions: there is no indication from
late-time photometry that the luminosity is powered by 56Ni, the broad
lightcurves suggest very large ejected masses, and the slow spectral evolution
is quite different from typical Ic timescales. The nature of the progenitor
stars and the origin of the luminosity are intriguing and open questions.

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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: cond-mat