Constraints on Ψ_c as a function of m_ϕ using the EPTA DR2new dataset from Paper III. Previous analyses are shown for comparison, cf. Porayko & Postnov (2014), Porayko et al. (2018) for further details. The blue, orange and brown lines represent the 95% Bayesian upper limit on Ψ_c obtained from the EPTA DR2new dataset with the correlated, uncorrelated and pulsar correlated analysis, respectively. The purple line shows the expected ULDM abundance computed from Eq. (32).