Simultaneous radio and X-ray observations of PSR B0611+22

TL;DR

This study presents simultaneous radio and X-ray observations of PSR B0611+22, revealing complex burst behaviors, frequency-dependent phase variations, and an upper limit on X-ray emission, advancing understanding of pulsar emission mechanisms.

Contribution

It provides the first simultaneous multi-frequency radio and X-ray analysis of PSR B0611+22, uncovering frequency-dependent burst correlations and phase behaviors.

Findings

Bursts are correlated at 327/150 MHz but anti-correlated at 820/150 MHz.

The pulsar's flux density at 327 MHz is lower than expected, indicating intrinsic behavior.

Bursting exhibits temporal variance and quasi-periodicity over hours.

Abstract

We report results from simultaneous radio and X-ray observations of PSR B0611+22 which is known to exhibit bursting in its single-pulse emission. The pulse phase of the bursts vary with radio frequency. The bursts are correlated in 327/150~MHz datasets while they are anti-correlated, with bursts at one frequency associated with normal emission at the other, in 820/150~MHz datasets. Also, the flux density of this pulsar is lower than expected at 327~MHz assuming a power law. We attribute this unusual behaviour to the pulsar itself rather than absorption by external astrophysical sources. Using this dataset over an extensive frequency range, we show that the bursting phenomenon in this pulsar exhibits temporal variance over a span of few hours. We also show that the bursting is quasi-periodic over the observed band. The anti-correlation in the phase offset of the burst mode at different frequencies suggests that the mechanisms responsible for phase offset and flux enhancement have different dependencies on the frequency. We did not detect the pulsar with XMM-Newton and place a 99$\%$ confidence upper limit on the X-ray efficiency of $ 10^{-5}$.