Orateur
Description
We explore the sensitivity to alternative gravitational wave polarisations in current and future pulsar timing array (PTA) datasets. We focus on the Scalar-Transverse (ST) mode, which is not present in a purely quadrupolar (Traceless-Transverse or TT) gravitational wave background as predicted by General Relativity. Our analysis is based on the MeerKAT Pulsar Timing Array dataset, which routinely monitors over 80 millisecond pulsars with a median timing precision∼1 𝜇s and presented its first evidence for nanohertz GWB after only 4.5 yr of observations. We simulate GWB with a multiple strain amplitudes and search for TT-only or ST and monopolar signals combined with the TT modes. We create extended simulations to include (i) an MPTA-based PTA with a 15-year observing baseline and (ii) a PTA with a uniform distribution of 140 pulsars across Southern and Northern hemispheres. I will present the results of these simulations and their implications.