SPIN EQUILIBRIUM WITH OR WITHOUT GRAVITATIONAL WAVE EMISSION: THE CASE OF XTE J1814-338 AND SAX J1808.4-3658

摘要

In this Letterwe present a newanalysis of the torques acting on the accretingmillisecond X-ray pulsarsSAXJ1808.4-3658 and XTE J1814-338, and showhowour results can be used to constrain theoretical models of the spin evolution. In particular, we find upper limits on any spin-up/down phase of XTE J1814-338 of |ν| ≤ 1.5 × 10~(-14) Hz s~(-1) at 95% confidence level. We examine the possibility that a gravitational wave torque may be acting in these systems and suggest that a more likely scenario is that both systems are close to spin equilibrium, as set by the disk/ magnetosphere interaction.