Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pulsar observations with the Fermi LAT: what we have seen   A year after \emph{Fermi} was launched, the number of known gamma-ray pulsars
has increased dramatically. For the first time, a sizable population of pulsars
has been discovered in gamma-ray data alone. For the first time, millisecond
pulsars have been confirmed as powerful sources of gamma-ray emission, and a
whole population of these objects is seen with the LAT. The remaining gamma-ray
pulsars are young pulsars, discovered via an efficient collaboration with radio
and X-ray telescopes. It is now clear that a large fraction of the nearby
energetic pulsars are gamma-ray emitters, whose luminosity grows with the
spin-down energy loss rate. Many previously unidentified EGRET sources turn out
to be pulsars. Many of the detected pulsars are found to be powering pulsar
wind nebulae, and some are associated with TeV sources. The \emph{Fermi} LAT is
expected to detect more pulsars in gamma rays in the coming years, while
multi-wavelength follow ups should detect \emph{Fermi}-discovered pulsars. The
data already revealed that gamma-ray pulsars generally emit fan-like beams
sweeping over a large fraction of the sky and produced in the outer
magnetosphere.

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The categories of this paper are: hep-th
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
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The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat