Precision Timing of PSR J0437-4715 with the IAR Observatory and Implications for Low-Frequency Gravitational Wave Source Sensitivity

TL;DR

This paper discusses how high-precision timing of pulsar PSR J0437-4715 at the IAR Observatory can significantly enhance the sensitivity of gravitational wave detection efforts, especially in the southern sky.

Contribution

It demonstrates that modest upgrades at IAR can improve pulsar timing sensitivity, filling a critical gap in current gravitational wave detection arrays.

Findings

IAR can achieve high-precision timing despite smaller antennas.

Upgrades could increase sensitivity by a factor of 2-4 over 10 years.

Including this pulsar improves sky coverage for gravitational wave searches.

Abstract

While observations of many high-precision radio pulsars of order $\lesssim1~\mu$s across the sky are needed for the detection and characterization of a stochastic background of low-frequency gravitational waves (GWs), sensitivity to single sources of GWs requires even higher timing precision. The Argentine Institute of Radio Astronomy (IAR; Instituto Argentino de Radioastronom\'ia) has begun observations of the brightest-known millisecond pulsar, J0437$-$4715. Even though the two antennas are smaller than other single-dish telescopes previously used for pulsar timing array (PTA) science, the IAR's capability to monitor this pulsar daily coupled with the pulsar's brightness allows for high-precision pulse arrival-time measurements. While upgrades of the facility are currently underway, we show that modest improvements beyond current plans will provide IAR with unparalleled sensitivity to this pulsar. The most stringent upper limits on single GW sources come from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). Observations of PSR J0437$-$4715 will provide a significant sensitivity increase in NANOGrav's "blind spot" in the sky where fewer pulsars are currently being observed. With state-of-the-art instrumentation installed, we estimate the array's sensitivity will improve by a factor of $\approx$2-4 over 10 years for 20% of the sky with the inclusion of this pulsar as compared to a static version of the PTA used in NANOGrav's most recent limits. More modest instrumentation result in factors of $\approx$1.4-3. We identify four other candidate pulsars as suitable for inclusion in PTA efforts. International PTA efforts will also benefit from inclusion of these data given the potential achievable sensitivity.