An updated glitch rate-age law inferred from radio pulsars

Radio pulsar glitches probe far-from-equilibrium processes involving stress accumulation and relaxation in neutron star interiors. Previous studies of radio pulsar glitch rates have focused on individual pulsars with as many recorded glitches as possible. In this work we analyze glitch rates using all available glitch data, including objects that have glitched never or once. We assume the glitch rate follows a homogeneous Poisson process. Calculating relevant Bayes factors shows that a model in which the glitch rate λ scales as a power of the characteristic age τ is preferred over models which depend arbitrarily on powers of the spin frequency ν and/or its time derivative. For the preferred model λ=A(τ/τ_ref)^γ where τ_ref=1 yr is a reference time, we produce Bayesian posterior distributions on A and γ using both the data set containing pulsars with one or more observed glitches, and a new data set where objects with zero recorded glitches are included. The updated estimates still support increased glitch activity for younger pulsars, while demonstrating that the large number of objects with zero glitches contain important statistical information about the rate, provided that they are part of the same population as opposed to a disjoint population which never glitches for some unknown physical reason.