Speaker
Description
Pulsars provide exceptionally stable astrophysical clocks, but precision timing at low radio frequencies is complicated by changes in their observed pulse profiles across the observing band. Such frequency-dependent profile evolution can introduce systematic offsets in measured pulse arrival times if a single frequency-averaged template is used. We investigate how frequency resolution can be optimised to mitigate these effects using realistic simulated observations spanning 300–500 MHz, representative of uGMRT Band-3 data. Our simulations incorporate several forms of frequency-dependent pulse-shape evolution, including changes in pulse width, component separation, and relative component amplitudes. We compare pulse arrival times obtained using fully frequency-resolved templates with those derived from progressively finer frequency-averaged subbands, and use statistical model-selection tests to determine when additional frequency-dependent timing corrections are required. We find that frequency-resolved templates naturally account for the evolving pulse shape, while frequency-averaged templates require an appropriate number of subbands to minimise residual frequency-dependent timing structure. In the representative simulation, this transition occurs at 64 subbands across the 200-MHz band. Our results demonstrate that statistically motivated template construction and subband selection can improve the reliability and precision of low-frequency pulsar timing, with broader implications for pulsars as precision astrophysical clocks.