XMM-Newton and NuSTAR Observations of the Compact Millisecond Pulsar Binary PSR J1653–0158

Abstract

Abstract We have presented the first joint XMM-Newton and NuSTAR analysis of the millisecond pulsar (MSP) binary PSR J1653−0158. The 75 minute orbital period inferred from optical and gamma-ray observations together with the 1.97 ms pulsation in the gamma-rays indicate that this system is the most compact Black Widow MSP system known to date. The orbital period was not detected in the XMM-Newton and NuSTAR data, probably due to insufficient photon counts obtained in the observations. Fitting the joint X-ray spectrum of PSR J1653−0158 with a power law gives a photon index Γ = 1.71 ± 0.09. The X-ray luminosity of the source in the (0.2–40) keV band is deduced to be 1.18 × 1031 erg s−1, for an adopted distance of 0.84 kpc. We have shown that the broadband X-ray spectrum can be explained by synchrotron radiation from electrons accelerated in the intrabinary shock, and the gamma-rays detected in the Fermi data are curvature radiations from electrons and positrons in the pulsar magnetosphere. Our kinematic analysis of the Tidarren systems PSR J1653–0158 and PSR J1311–3430 indicates that the two Tidarren systems are likely to have originated in the Galactic disk.