A state change in the low-mass X-ray binary XSS J12270-4859

作者：Bassa C G^*; Patruno A; Hessels J W T; Keane E F; Monard B; Mahony E K; Bogdanov S; Corbel S; Edwards P G; Archibald A M; Janssen G H; Stappers B W; Tendulkar S

来源：Monthly Notices of the Royal Astronomical Society, 2014, 441(2): 1825-1830.

DOI：10.1093/mnras/stu708

• binaries: general
• stars: individual: XSS J12270-4859
• stars: neutron
• X-rays: binaries

Millisecond radio pulsars acquire their rapid rotation rates through mass and angular momentum transfer in a low-mass X-ray binary system. Recent studies of PSR J1824-2452I and PSR J1023+0038 have observationally demonstrated this link, and they have also shown that such systems can repeatedly transition back-and-forth between the radio millisecond pulsar and low-mass X-ray binary states. This also suggests that a fraction of such systems are not newly born radio millisecond pulsars but are rather suspended in a back-and-forth, state-switching phase, perhaps for gigayears. XSS J12270-4859 has been previously suggested to be a low-mass X-ray binary, and until recently the only such system to be seen at MeV-GeV energies. We present radio, optical and X-ray observations that offer compelling evidence that XSS J12270-4859 is a low-mass X-ray binary which transitioned to a radio millisecond pulsar state between 2012 November 14 and December 21. We use optical and X-ray photometry/spectroscopy to show that the system has undergone a sudden dimming and no longer shows evidence for an accretion disc. The optical observations constrain the orbital period to 6.913 +/- 0.002 h.

• 出版日期2014-6
• 单位中国地震局