PSR J1023+0038 optical spectra

This may point to episodes of matter ejection from the inner regions of the accretion disc, possibly associated with switches to low modes. Doppler tomography of the Halpha and Hbeta emission lines indicates possible asymmetric emission structures, consistent with a scenario in which part of the accreting material is expelled from the system. In addition, the optical continuum shows variability consistent with a possible orbital modulation associated with the irradiated companion star, although its characterisation is limited by the observing conditions.

Our results provide new constraints on the short-timescale behaviour of tMSPs in the sub-luminous disc state and support scenarios in which accretion and outflow processes coexist. Further multiwavelength observations, particularly with simultaneous X-ray coverage, will be crucial to establish a direct link between the observed optical variability and the switches between the high and low modes.