X-ray and Radio Variabilities of PSR J2032+4127 near Periastron

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • C.-Y. Ng
  • W. C. G. Ho
  • E. V. Gotthelf
  • J. P. Halpern
  • Malcolm J. Coe
  • Andrew Lyne
  • K. S. Wood
  • M. Kerr


We present X-ray and radio monitoring observations of the gamma-ray binary PSR J2032+4127/MT91 213 during its periastron passage in late 2017. Dedicated Chandra, XMM-Newton, NuSTAR X-ray observations and VLA radio observations of this long orbit (50 years), 143 ms pulsar/Be star system clearly revealed flux and spectral variability during the passage. The X-ray spectrum hardened near periastron, with a signicant decrease in the power-law photon index from Γ ≈ 2 to 1.2 and evidence of an increased absorption column density. We identied a possible spectral break at a few keV in the spectrum that suggests synchrotron cooling. A coincident radio and X-ray are occurred one week after periastron, which is possibly the result of the pulsar wind interacting with the Be stellar disk and generating synchrotron radiation. However, a multi-wavelength comparison indicate that the X-ray and radio spectra cannot be simply connected by a single power-law component. Hence, the emission in these two energy bands must originate from different particle populations.

Bibliographical metadata

Original languageEnglish
JournalThe Astrophysical Journal
Early online date5 Aug 2019
Publication statusPublished - Aug 2019