Constraining Pulsar Emission Physics through Radio/Gamma-Ray Correlation of Crab Giant Pulses

TL;DR

This study investigates the correlation between radio giant pulses and gamma-ray emissions from the Crab pulsar to test emission models, using simultaneous observations at multiple radio telescopes and Fermi gamma-ray data.

Contribution

First simultaneous multi-wavelength campaign to test the Lyutikov (2007) model of pulsar giant pulse emission mechanisms.

Findings

Preliminary results from 20 hours of GBT observations at 8.9 GHz.

Ongoing observations with Jodrell Bank and Green Bank telescopes.

No definitive correlation established yet between radio GPs and gamma-ray photons.

Abstract

To constrain the giant pulse (GP) emission mechanism and test the model of Lyutikov (2007) of GP emission, we are carrying out a campaign of simultaneous observations of the Crab pulsar between gamma-rays (Fermi) and radio wavelengths. The correlation between times of arrival of radio GPs and high-energy photons, whether it exists or not, will allow us to choose between different origins of GP emission and further constrain the emission physics. Our foremost goal was testing whether radio GPs are due to changes in the coherence of the radio emission mechanism, variations in the pair creation rate in the pulsar magnetosphere, or changes in the beaming direction. Accomplishing this goal requires an enormous number of simultaneous radio GPs and gamma-photons. Thus, we organized a radio observations campaign using the 42-ft telescope at the Jodrell Bank Observatory (UK), the 140-ft telescope, and the 100-m Robert C. Byrd Green Bank Telescope (GBT) at the Green Bank Observatory (WV). While the observations with the two first ones are ongoing, here we present the preliminary results of 20 hrs of observations with the GBT at the high frequency of 8.9 GHz. These particular observations were aimed to probe the model of GP emission by Lyutikov (2007) which predicts that GPs at frequencies > 4 GHz should be accompanied by gamma-ray photons of energies of 1-100 GeV.