Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gamma-ray observations of the Be/pulsar binary 1A 0535+262 during a
  giant X-ray outburst   Giant X-ray outbursts, with luminosities of about $ 10^{37}$ erg s$^{-1}$,
are observed roughly every 5 years from the nearby Be/pulsar binary 1A
0535+262. In this article, we present observations of the source with VERITAS
at very-high energies (VHE; E$>$100 GeV) triggered by the X-ray outburst in
December 2009. The observations started shortly after the onset of the
outburst, and they provided comprehensive coverage of the episode, as well as
the 111-day binary orbit. No VHE emission is evident at any time. We also
examined data from the contemporaneous observations of 1A 0535+262 with the
Fermi/LAT at high energy photons (HE; E$>$0.1 GeV) and failed to detect the
source at GeV energies. The X-ray continua measured with the Swift/XRT and the
RXTE/PCA can be well described by the combination of blackbody and Comptonized
emission from thermal electrons. Therefore, the gamma-ray and X-ray
observations suggest the absence of a significant population of non-thermal
particles in the system. This distinguishes 1A~0535+262 from those Be X-ray
binaries (such as PSR B1259--63 and LS I +61$^{\circ}$303) that have been
detected at GeV--TeV energies. We discuss the implications of the results on
theoretical models.

18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph