Here we present a study of the radio frequency eclipses of the black widow pulsar J1810+1744 at low frequencies, where we are most sensitive to small deviations in the effects of material along the line of sight. Utilising the simultaneous dual beamforming and interferometric (imaging) mode of LOFAR High Band Antenna, pulsar flux variations throughout the orbit are compared for the two observing techniques to test for the presence of scattering and absorption at eclipse orbital phases. Dispersion measure and scattering variations are used as a sensitive probe into outermost edges of the eclipsing material surrounding the companion star. We find the eclipsing medium to be variable on timescales shorter than the 3.6 hr orbital period, and propose cyclotron-synchrotron absorption as the most likely primary eclipse mechanism.

The Crab pulsar was first detected soon after the discovery of pulsars, and has long been studied for its unique traits. One of these traits, giant pulses that can be upwards of 1000 times brighter than the average pulse, was key to the Crab’s initial detection. Giant pulses are only seen in a few pulsars, and their energy distributions distinguish them from normal pulsed emission. There have been many studies over a period of decades to measure the power-law slope of these energy distributions, which provide insight into the possible emission mechanism of these giant pulses.

The 42-foot telescope at Jodrell Bank Observatory monitors the Crab pulsar on a daily basis. We have single-pulse data dating back to 2012, containing roughly 1,000,000 giant pulses, the largest sample of Crab giant pulses to date. This large set of giant pulses allows us to do a range of science, including pulse-width studies and in-depth studies of giant-pulse energy distributions. The latter are particularly interesting, as close inspection of the high-energy tail of the energy distribution allows us to investigate the detectability of extragalactic giant-pulsing pulsars. Also, by calculating rates from these energy distributions, we may be able to shed light on a possible link between Fast Radio Bursts and giant pulses.

We present high-sensitivity XMM/LOFAR observations that show for the first time that mode switching extends from radio to X-ray. In pulsar B0943+10, the known changes in radio profile and drift rate are confidently tied to simultaneous changes in X-ray emission.

In mode switching, seen in many pulsars, profile and subpulse-drift behavior change almost instantaneously. The mechanism for these drastic changes, or for the bi-stable emission behavior, is not understood; while even for the basic emission mechanism different families of theories (e.g. vacuum gap, or space-charge limited flow models) exist.

To discriminate between such models, we carried out a campaign of 42 hours of simultaneous LOFAR/XMM-Newton observations on PSR B0943+10. Through LOFAR's unparalleled low-frequency sensitivity, mode changes were pinpointed to 10-second accuracy. XMM X-ray photons were next separated by the two radio modes. We discovered large modal differences in the X-ray pulsations, flux, and spectral shapes: in the radio-bright mode, no X-ray pulsations are detected – but in the radio-quiet mode, B0943+10 is strongly pulsating in X-ray.

As the quantity and quality of timing data improves, we have reached the point at which the difference between timing noise and small glitches is unclear. As a consequence, the number of events reported as glitches which show unusual properties, quite different to those of giant glitches, has increased. For example, there is now a substantial population of glitches that apparently involve a decrease in spin-down rate rather than an increase. Motivated by the theoretical implications of such a result, we are conducting a detailed review of how glitches are detected and characterised. We have focused on three main questions: the observational biases affecting glitch detection; the methods used to characterise error bars on changes in spin and spin derivatives; and the physical mechanisms that could potentially explain the different populations of timing irregularities, in the light of improved characterisation. While glitches are thought to be a consequence of the internal dynamics of the star, magnetospheric processes may be responsible for other irregularities, as timing noise and peculiar glitch recoveries. We report the first results from this study, using a small sample of radio pulsars that exhibit a wide variety of glitching behaviour.

Although optical pulsar studies have been limited to a few favoured objects, the observation of pulsars at optical wavelengths provides an opportunity to derive a number of important pulsar characteristics, including the energy spectrum of the emitting electrons and the geometry of the emission zone. These parameters will be vital for a comprehensive model of pulsar emission mechanisms. Observations of the Crab pulsar with the high-time-resolution photon-tagging photometer IquEYE show an optical–radio delay of ~178 μs. Incorporating simultaneous Jodrell Bank radio observations suggested a correlation between giant radio pulses and enhanced optical pulses for this pulsar, thus offering possible evidence for the reprocessing of radio photons.