Posterior distribution of the source parameters at z = 9.1 for the Varying A_r scenario. These models are favoured by the LOFAR upper limits from Acharya et al. (2024c). Magenta indicates the case in which upper limits in three k−bins are considered, while teal represents the case when only one k−bin is used. The contour levels in the two-dimensional contour plots refer to the 1σ and 2σ credible intervals of the models favoured by the LOFAR upper limit at this redshift. The diagonal panels represent the corresponding marginalised probability distributions of each parameter.