Observed X‐ray/Radio Correlation in the Vela Pulsar

We report the results of simultaneous observations of the Vela pulsar in X‐rays and radio from the RXTE satellite and the Mount Pleasant Radio Observatory in Tasmania. We sought correlations between the Vela's X‐ray emission and radio arrival times on a pulse by pulse basis. At a confidence level of 99.8% we have found significantly higher flux density in Vela's main X‐ray peak during radio pulses that arrived early. This excess flux shifts to the ‘trough’ following the 2nd X‐ray peak during radio pulses that arrive later. Our results suggest that the mechanism producing the radio pulses is intimately connected to the mechanism producing X‐rays. Current models using resonant absorption of radio emission in the outer magnetosphere as a cause of the X‐ray emission are explored as a possible explanation for the correlation.