The correlation between glitch activity and pulse profile changes for the Crab pulsar

Abstract

Using the archival data of the Neutron star Interior Composition Explorer, we study the evolution of two-peak phase separations of the Crab pulsar’s X-ray pulse profiles, and present a possible method to predict the next glitch epochs of the Crab pulsar. The phase separations increased with time in a form of quasi-periodic fluctuation. We fit the evolution of the phase separations by using a magic wave function (MW model). It is found that the increasing rates of the phase separation are $9.798^{\circ}\pm8.997^{\circ}$ and $7.842^{\circ} \pm5.112^{\circ}$ per century at 0.3–1.2 keV and 2–6 keV bands, respectively. The fluctuation periods of the phase separation at 0.3–1.2 keV and 2–6 keV bands are $124.907\pm4.936$ and $121.478\pm3.149$ days, respectively. Using the fitting results, we predict that one to three glitch activities would be observed during January and September 2020. It could be useful for guiding the telescopes timely and effectively observe the glitch activities of the Crab pulsar in the future.