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.
Digital Commons Citation
Bilous, A. V.; Kondratiev, V. I.; McLaughlin, M. A.; Ransom, S. M.; Lyutikov, M.; Mickaliger, M.; and Langston, G. I., "Correlation Of Fermi Photons With High-Frequency Radio Giant Pulses From The Crab Pulsar" (2011). Faculty Scholarship. 496.
Bilous, A. V., Kondratiev, V. I., Mclaughlin, M. A., Ransom, S. M., Lyutikov, M., Mickaliger, M., & Langston, G. I. (2011). Correlation Of Fermi Photons With High-Frequency Radio Giant Pulses From The Crab Pulsar. The Astrophysical Journal, 728(2), 110. http://doi.org/10.1088/0004-637X/728/2/110