System mass constraints for the accreting millisecond pulsar XTE J1814-338 using Bowen fluorescence

Understand

We present phase-resolved spectroscopy of the millisecond X-ray pulsar XTE J1814-338 obtained during its 2003 outburst.

• The spectra are dominated by high-excitation emission lines of HeII $\lambda$4686, H$\beta$, and the Bowen blend CIII/NIII 4630-50\AA.
• We exploit the proven Bowen fluorescence technique to establish a complete set of dynamical system parameter constraints using bootstrap Doppler tomography, a first for an accreting millisecond X-ray pulsar binary.
• The reconstructed Doppler map of the NIII $\lambda$4640 Bowen transition exhibits a statistically significant (>4$\sigma$) spot feature at the expected position of the companion star.