Speaker
Description
Pulsars, highly magnetized rotating neutron stars, exhibit sudden rotational frequency changes called glitches. These events provide insights into neutron star interiors, where extreme conditions govern matter behaviour. When the distribution of glitch sizes is bimodal, it is an indication that two trigger mechanisms are responsible for the glitches. On the other hand, a strong correlation between glitch size and inter-glitch time suggests that only a single mechanism is involved. The said correlation is significant in pulsars with high glitch frequency, notably PSR J0537-6910. Paradoxically, pulsars with significant correlations are reported to exhibit bimodal glitch size distributions, contradicting expectations. We therefore, compare correlations and size distributions in the 9 pulsars that have 10 glitches and above. Based on current understanding, a coexistence of significant correlations between glitch size and interglitch time with bimodal glitch size distributions challenges the single-vs-dual mechanism explanation, indicating that more complex processes are at play. The collective glitch size distribution of the pulsars is bimodal with the usual dip at 10-7 which is the demarcation for large and small glitch sizes. Large glitch sizes dominate in J0537-6910, J0835-4510, J13416220 and J1413-6141 while small glitches are dominant in J1740-3015, J0534+2200, J06311036, J1801-2304 and J1048-5832. All of these independently have continuous glitch size distributions except J0631+1036 which is discontinuous at 10-7 where the dip occurs for the bimodal distributions. This indicates possible dual sources acting independently. J0537-6910, J1341-6220, J1801-2304, J1413-6141 and J1048-5832 show positive Spearman correlations of 0.938, 0.619 0.714, 0.819 and 0.764 respectively while J0631+1036 has 0.929 positive Pearson correlation for the glitch size – waiting time correlations. Our results suggest that J0631+1036 portrays the correlation – bimodal paradox. This is possible if small glitches are triggered by the individual mechanisms independently while large glitches occur when both mechanisms occur simultaneously. More robust methods are needed to uncover underlying patterns.
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