The MeerKAT Pulsar Timing Array: Results of the first searches for gravitational waves

The signal that is most sought after in pulsar timing array experiments is that of a stochastic gravitational wave background: the superposition of all nanohertz-frequency gravitational waves emitted in the observable Universe. Recently, a number of pulsar timing arrays have unveiled the first evidence of a spatially correlated signal. This signal, if correct, is thought to be representative of a background of gravitational waves from inspiralling supermassive black hole binaries. However, in order to make a definitive detection, it is necessary to observe pulsars over a longer timing baseline, monitor a larger ensemble of pulsars, time pulsars to higher precision, or all. Here, we introduce The MeerKAT Pulsar Timing Array. The array monitors a large number of pulsars (83), to high precision, and at the highest cadence of any extant pulsar timing array. In the pursuit of a definitive detection of nanohertz-frequency gravitational waves, it now joins the others in searching its dataset for signals indicative of a stochastic gravitational wave background, and entertains more exotic explanations for the surprising results found in this search.

In this presentation, we describe the process of analysing the highly sensitive data of the array, and present the detailed results of these searches.