Recent multi-wavelength observations have provided valuable insights into the behavior of PSR J1023+0038, a transitional millisecond pulsar. This system alternates between rotation-powered and accretion-powered states, offering a unique opportunity to study neutron star dynamics.
In February 2025, a comprehensive study was conducted using simultaneous X-ray, ultraviolet (UV), optical, and radio observations. The findings revealed that during X-ray flares, UV and optical counterparts were present, coinciding with significant radio flares. Notably, the optical polarization decreased during these events, indicating the emergence of an unpolarized component. These observations suggest that the thickening of the inner accretion disc may enhance the ionization level, generating more free electrons that could be channeled by magnetic field lines into the jet, thereby driving the associated radio and optical variability. The radio spectral evolution during flares aligns with synchrotron self-absorption in jet ejecta or internal shocks within the compact jet. The study also inferred radio polarization upper limits, supporting a compact jet origin but not ruling out discrete ejections. These findings highlight the potential of transitional millisecond pulsars as laboratories for investigating jet-launching mechanisms, especially under low mass accretion rates.
In July 2025, an international team of researchers, including members from the University of Oxford, conducted a multi-band polarimetric campaign on PSR J1023+0038. Observations were made using NASA's Imaging X-ray Polarimetry Explorer (IXPE), the Very Large Telescope (VLT), and the Karl G. Jansky Very Large Array (VLA). The study found a consistent polarization orientation across X-ray and optical wavelengths, suggesting a single, coherent physical process driving the pulsar's broadband emission. However, the radio observations revealed no detectable polarization, indicating that the radio emission arises from a separate, jetted outflow of relativistic particles. This absence of radio polarization provides strong evidence for two distinct high-energy particle acceleration zones within the system. These coordinated observations underscore the critical role of multi-band campaigns in unlocking the physics of exotic stellar remnants.
These recent studies enhance our understanding of the complex interplay between accretion, magnetic fields, and high-energy outflows in transitional millisecond pulsars, offering deeper insights into neutron star behavior and evolution.