Does the accreting millisecond pulsar XTE J1814-338 precess?

Abstract

Accretion‐powered pulsars with slight ellipticites are expected to precess, producing characteristic variations in their pulse properties. We compute light curves for various geometric configurations of a precessing pulsar and predict the periodic modulation of the mean flux, pulse‐phase residuals and fractional amplitudes of the pulse profiles. We then search for these signatures in 37 days of X‐ray timing data from the accreting millisecond pulsar XTE J1814—338. We analyze a 12.2‐d modulation observed previously and show that it is consistent with a freely precessing neutron star only if the inclination angle is <0.1°, an a priori unlikely orientation. If the observed flux variations are d..