Pulsar observations with European telescopes for testing gravity and detecting gravitational waves

TL;DR

This paper discusses the use of European radio telescopes, especially the LEAP array, to detect nanohertz gravitational waves via pulsar timing, and explores monitoring strong-gravity systems for testing gravity theories.

Contribution

It reports on the progress of the LEAP collaboration, including the addition of the Sardinia Radio Telescope, and highlights methods to improve pulsar timing precision for gravitational wave detection.

Findings

Successful integration of Sardinia Radio Telescope into LEAP

Enhanced pulsar timing precision through coherent addition

Strong constraints on gravitational wave background established

Abstract

A background of nanohertz gravitational waves from supermassive black hole binaries could soon be detected by pulsar timing arrays, which measure the times-of-arrival of radio pulses from millisecond pulsars with very high precision. The European Pulsar Timing Array uses five large European radio telescopes to monitor high-precision millisecond pulsars, imposing in this way strong constraints on a gravitational wave background. To achieve the necessary precision needed to detect gravitational waves, the Large European Array for Pulsars (LEAP) performs simultaneous observations of pulsars with all five telescopes, which allows us to coherently add the radio pulses, maximize the signal-to-noise of pulsar signals and increase the precision of times-of-arrival. We report on the progress made and results obtained by the LEAP collaboration, and in particular on the addition of the Sardinia Radio Telescope to the LEAP observations during its scientific validation phase. In addition, we discuss how LEAP can be used to monitor strong-gravity systems such as double neutron star systems and impose strong constraints on post-keplerian parameters.