The 2016 Vela glitch: a key to neutron star internal structure and dynamics

High-resolution, pulse-to-pulse observation of the 2016 Vela glitch and its relaxation provided an opportunity to probe the neutron star internal structure and dynamics with unprecedented detail. We use the observations of this glitch to infer superfluid characteristics in the framework of the vortex creep model. The glitch rise time constraint of 12.6 s put stringent limits on the angular momentum exchange between the crustal superfluid and the observed crust. Together with the observed excess acceleration in the rotation rate as compared to the post-glitch equilibrium value, this discriminates crustal superfluid-crust lattice and core superfluid-crustal normal matter coupling time-scales. An evident decrease in the crustal rotation rate immediately before the glitch is consistent with the formation of a new vortex trap zone that initiates the large-scale vortex unpinning avalanche. Formation of vortex trap by a crust breaking quake induces short-lived magnetospheric changes. The long-term post-glitch spin-down rate evolution reveals the moments of inertia and recoupling time-scales of the superfluid layers participating in the glitch and leads to an estimation of the time to the next glitch that agrees with the time interval between the 2016 and 2019 glitches. Our results are consistent with theoretical estimates of effective neutron and proton masses in the superfluid. We also constrain the vortex line-flux tube pinning energy per intersection as 2 MeV. 2020 The Author(s)