Posterior distribution of the disfavoured values of the IGM parameters for the A_r = 0 scenario. These are disfavoured by the LOFAR upper limits from Mertens et al. (2025) at z = 9.1. Red refers to the case when z = 9.1 is considered separately (Single-z), while blue represents the joint redshift analysis obtained at z = 9.1 (Joint-z). The contour levels in the two-dimensional contour plots refer to the 1σ and 2σ credible intervals of the models disfavoured by the LOFAR upper limit at this redshift. The diagonal panels represent the corresponding marginalised probability distributions of each parameter.