Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral variability modes of GX 339-4 in a hard-to-soft state
  transition   We report on INTEGRAL observations performed during the 2004 outburst of the
bright black hole transient GX 339-4. We analysed IBIS and JEM-X public data
starting on 9th August and lasting about one month. During this period GX 339-4
showed spectral state transitions. In order to seek for variability patterns, a
principal component analysis (PCA) has been used.

0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat