Quantifying Selection Effects in Radio Pulsar Mass Measurements

Neutron star mass measurements from radio pulsars provide key constraints on the nuclear equation of state and tests of strong-field gravity. However, pulsar mass inference involves two distinct stages, (1) initial detection and (2) timing analysis, each subject to its own selection effects. In the first stage, pulsar detectability in compact binaries is reduced by Doppler smearing from orbital motion, which depends on system masses through Keplerian dynamics and introduces mass-dependent detection biases. In the second stage, mass inference from Shapiro delay and other post-Keplerian parameters introduces additional measurement biases. To quantify these effects, we employ a hierarchical population-inference framework analogous to those used in gravitational-wave analyses, incorporating an explicit selection function for the intrinsic neutron star mass distribution. This approach reveals how selection effects shape the observed mass distribution of pulsar populations and informs future joint population studies with gravitational-wave and radio data.