Special Astrophysics Seminar

hat XMM X-ray and Arecibo Radio Observations of Pulsar B0823+26 Have to Teach Us

Joanna Rankin

University of Vermont

Pulsar B0823+26 was shown recently (Sobey et al. 2015) to assume a quiet emission mode about 100 times weaker than its usual bright mode during about 15% of the time. Simultaneous radio/X-ray observations (Hermsen et al. 2018) then showed a hot polar cap during the bright mode that nearly disappeared in the weak mode. B0823+26 is a nearly orthogonal two-pole interpulsar (with a further postcursor feature), and its PPA traverse allows us to model its sightline geometry accurately. The pulsar?s profile forms and single-pulse dynamics change drastically between its bright and weak modes, suggesting that different pair-plasma source mechanisms may predominate in the two modes as well as different radio emission-beam configurations. We will summarize what sensitive Arecibo radio observations show us about the pulsar?s emission in its two modes and attempt to interpret these effects in terms of the pulsar?s radio/X-ray behavior.