Discovery of X-ray pulsations in the Be/X-ray binary IGR J21343+4738

TL;DR

This paper reports the discovery of X-ray pulsations in the Be/X-ray binary IGR J21343+4738, revealing details about its pulse period, spectrum, and accretion mechanisms during a specific observation.

Contribution

First detection of X-ray pulsations in IGR J21343+4738, providing insights into its spectral properties and accretion processes despite the circumstellar disc's absence.

Findings

Pulse period of 320.35 seconds identified.

Spectrum fits a two-component model with blackbody and power law.

X-ray luminosity suggests accretion via low-velocity wind.

Abstract

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 seconds. The pulse profile displays a peak at low energy that flattens at high energy. The pulse fraction is 45+-3$% and independent of energy within the statistical uncertainties. The 0.2-12 keV spectrum is well fit by a two component model consisting of a blackbody with kT=0.11+-0.01 keV and a power law with photon index Gamma=1.02+-0.07. Both components are affected by photoelectric absorption with a equivalent hydrogen column density NH=(1.08+-0.15)x 10^{22} cm^{-2} The observed unabsorbed flux is 1.4x10^{-11} erg cm^{-2} s^{-1} 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~10^{35} erg s^{-1}) may result from accretion via a low-velocity equatorial wind from the optical companion.