Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nova Cygni 2001/2 = V2275 Cyg   We present an analysis of low- and medium resolution spectra of the very fast
nova, Nova Cygni 2001/2 (V2275 Cyg) obtained at nine epochs in August,
September and October, 2001. The expansion velocity from hydrogen Balmer lines
is found to be 2100 km/s, although early H-alpha profile showed a weak feature
at -3500 km/s, too. The overall appearance of the optical spectrum is dominated
by broad lines of H, He and N, therefore, the star belongs to the ``He/N''
subclass of novae defined by Williams (1992). Interstellar lines and bands, as
well as BV photometry taken from the literature yielded to a fairly high
reddening of E(B-V)=1.0+/-0.1 mag. The visual light curve was used to deduce
M_V by the maximum magnitude versus rate of decline relationship. The resulting
parameters are: t_0=2452141.4(+0.1)(-0.5), t_2=2.9+/-0.5 days, t_3=7+/-1 days,
M_V=-9.7+/-0.7 mag. Adopting these parameters, the star lies between 3 kpc and
8 kpc from the Sun.

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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
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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: math-ph
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The categories of this paper are: q-bio