Correlations between pulsed X-ray flux and radio arrival time in the Vela pulsar

Research paper by A. N. Lommen, J. Donovan, C. Gwinn, Z. Arzoumanian, A. Harding, M. Strickman, R. Dodson, P. McCulloch, D. Moffett

Indexed on: 04 Jan '07Published on: 04 Jan '07Published in: Astrophysics


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 and radio flux densities and radio arrival times on a pulse by pulse basis. We 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. We suggest that the mechanism producing the radio pulses is intimately connected to the mechanism producing X-rays. Current models using resonant absorption in the outer magnetosphere as a cause of the radio emission, and less directly of the X-ray emission, are explored as a possible explanation for the correlation.