Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multiwavelength Observations of GX 339-4 in 1996. III. Keck Spectroscopy   As part of our multiwavelength campaign of observations of GX 339-4 in 1996
we present our Keck spectroscopy performed on May 12 UT. At this time, neither
the ASM on the RXTE nor BATSE on the CGRO detected the source. The optical
emission was still dominated by the accretion disk with V approximately 17 mag.
The dominant emission line is H alpha, and for the first time we are able to
resolve a double peaked profile. The peak separation Delta v = 370 +/- 40 km/s.
Double peaked H alpha emission lines have been seen in the quiescent optical
counterparts of many black hole X-ray novae. However, we find that the peak
separation is significantly smaller in GX 339-4, implying that the optical
emission comes from a larger radius than in the novae. The H alpha emission
line may be more akin to the one in Cygnus X-1, where it is very difficult to
determine if the line is intrinsically double peaked because absorption and
emission lines from the companion star dominate.

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The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
2
The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: ao-sci
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th