Speaker
Dr
Anna Bilous
(Radboud University Nijmegen)
Description
PSR B0943+10 is one of the best examples of the rare class of mode-switching pulsars. Unlike most of the pulsar population, PSR B0943+10 has two stable modes of radio emission, each with its own distinct radio profile morphology and sinlge-pulse behaviour. The pulsar switches between "Bright" and "Quiet" modes once every few hours and the transition takes less than a few stellar rotations. The switch in the radio modes is also accompanied by changes in the X-ray emission mode (Hermsen et al. 2013) indicating that mode switching is a rapid and global transformation of the magnetosphere and its broadband emission. The exact nature of this transformation, however, is still far from being well understood. With the goal of better illuminating the difference between the two modes, we carried out sensitive, multi-hour LOFAR observations below 100 MHz, where the frequency-dependent changes in the pulse-profile morphology are the largest, and effects too subtle to see at higher frequencies become readily evident. We present detailed review of the pulsar's magnetospheric geometry, describe the frequency evolution of the average profile and constrain the emission regions in both modes within the frame of radius-to-frequency mapping theory. We also investigate the gradual changes in the shape of the average profile within a single mode instance. Finally, we explore drifting subpulses in the Bright mode and give a geometrical explanation for the discovered frequency-dependent delay in the drift phase.
Primary author
Dr
Anna Bilous
(Radboud University Nijmegen)
