Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical emission from GRB 050709: a short/hard GRB in a star forming
  galaxy   We present optical observations of the short/hard gamma-ray burst GRB 050709,
the first such event with an identified optical counterpart. The object is
coincident with a weak X-ray source and is located inside a galaxy at redshift
z = 0.1606 +- 0.0002. Multiband photometry allowed us to study the broad-band
spectral energy distribution. Late-time monitoring places strong limits on any
supernova simultaneous with the GRB. The host galaxy is not of early type.
Spectra show that the dominant stellar population is relatively young (~ 1
Gyr), and that ongoing star formation is present at a level of 2-3 (L/L*)
Msun/yr. This is at least 2 orders of magnitude larger than that observed in
the elliptical hosts of the short GRB 050509B and GRB 050724. This shows that
at least some short GRBs originate in a young population. Short/hard GRB models
based on the merger of a binary degenerate system are compatible with the host
galaxy characteristics, although there is still the possibility of a connection
between young stars and at least a fraction of such events.

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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: physics
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph