Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Correlation of Fermi photons with high-frequency radio giant pulses from
  the Crab pulsar   To constrain the giant pulse (GP) emission mechanism and test the model of
Lyutikov (2007) for GP emission, we have carried out a campaign of simultaneous
observations of the Crab pulsar at gamma-ray (Fermi) and radio (Green Bank
Telescope) wavelengths. Over 10 hours of simultaneous observations we obtained
a sample of 2.1x10^4 giant pulses, observed at a radio frequency of 9 GHz, and
77 Fermi photons, with energies between 100 MeV and 5 GeV. The majority of GPs
came from the interpulse (IP) phase window. We found no change in the GP
generation rate within 10-120 s windows at lags of up to +-40 min of observed
gamma-ray photons. The 95% upper limit for a gamma-ray flux enhancement in
pulsed emission phase window around all GPs is 4 times the average pulsed
gamma-ray flux from the Crab. For the subset of IP GPs, the enhancement upper
limit, within the IP emission window, is 12 times the average pulsed gamma-ray
flux. These results suggest that GPs, at least high-frequency IP GPs, are due
to changes in coherence of radio emission rather than an overall increase in
the magnetospheric particle density.

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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom