Pulsed Emission Energetics of X-ray Pulsars

Rotation-powered pulsars are thought to lose their spin-down energy to a particle wind. However, the exact mechanism for this is not fully understood. In particular, how the energy of the pulsar is partitioned between the pulsed and unpulsed emission remains an open question. In this report we reconsider the Seward and Wang (1988) L_x \ {vs.} \ ˙ E relationship for pulsed and unpulsed emission. We present phase-resolved spectroscopy in the 2-10 keV energy range for a sample of pulsars observed using ASCA, RXTE, SAX, and XMM archival data. We attempt to disentangle the two contributions and determine their ratio as a function of ˙ E using Chandra flux measurements and the new relationship of Gotthelf (2003) for the spectra of young pulsars. We present preliminary results on this project. We acknowledge support on this project from NASA Grant NAG 5-7935