2014MNRAS.442..472R

We report on the discovery of X-ray pulsations in the Be/X-ray binary IGR J21343+4738 during an XMM-Newton observation. We obtained a barycentric corrected pulse period of 320.35±0.06 s. The pulse profile displays a peak at low energy that flattens at high energy. The pulse fraction is 45±3 per cent and independent of energy within the statistical uncertainties. The 0.2-12 keV spectrum is well fitted by a two-component model consisting of a blackbody with kT = 0.11±0.01 keV and a power law with photon index Γ = 1.02±0.07. Both components are affected by photoelectric absorption with an equivalent hydrogen column density NH = (1.08±0.15)x10²²/cm2. The observed unabsorbed flux is 1.4x10^–11erg/cm2/s in the 0.2-12 keV energy band. Despite the fact that the Be star's circumstellar disc has almost vanished, accretion continues to be the main source of high-energy radiation. We argue that the observed X-ray luminosity (LX ∼ 10³⁵ erg/s) may result from accretion via a low-velocity equatorial wind from the optical companion.