Wide-band timing of GMRT discovered millisecond pulsars

TL;DR

This paper demonstrates that wide-band timing analysis of millisecond pulsars using the upgraded GMRT achieves high precision in measuring dispersion measure variations, comparable to narrow-band methods, and highlights its potential for pulsar timing arrays.

Contribution

The study introduces a wide-band timing method using PulsePortraiture for GMRT-discovered MSPs, improving DM measurement precision and profile modeling at low frequencies.

Findings

Wide-band timing achieves DM precision of 10^-4 pc cm^-3.

Results are comparable to narrow-band timing in DM and timing precision.

Profile modeling at low frequencies is effective for pulsar timing.

Abstract

Modeling of frequency-dependent effects, contributed by the turbulence in the free electron density of interstellar plasma, is required to enable the detection of the expected imprints from the stochastic gravitational-wave (GW) background in pulsar timing data. In this work, we present an investigation of temporal variations of interstellar medium for a set of millisecond pulsars (MSPs) with the upgraded GMRT aided by large fractional bandwidth at lower observing frequencies. Contrary to the conventional narrow-band analysis using a frequency invariant template profile, we applied $PulsePortraiture$ based wide-band timing analysis while correcting for the evolution of the pulsar profile with frequency. Implementation of $PulsePortraiture$ based wide-band timing method for the GMRT discovered MSPs to probe the DM variations resulted in a DM precision of $10^{-4}\,pc~cm^{-3}$. In general, we achieve similar DM and timing precision from wide-band timing compared to the narrow-band timing with matching temporal variations of DMs. This wide-band timing study of newly discovered MSPs over a wide frequency range highlights the effectiveness of profile-modeling at low frequencies and probes the potential of using them in pulsar timing array.