Chains from fitting the kination/stiff-amplified inflationary SGWB model to PTA free spectra (NANOGrav & EPTA)

Datasets of chain files from the Bayesian fitting analyses in Li, Meyers & Shapiro 2025, ApJ, 985:117 (https://iopscience.iop.org/article/10.3847/1538-4357/adcc14, arXiv: 2503.18937), corresponding to Figs. 2 & 3 in the paper. The authors considered an extended cosmological model with a possible early kination/stiff phase (with equation of state w=1). The kination/stiff-amplified inflationary SGWB is fitted to the PTA free spectra from NANOGrav and EPTA, using both current data and mock (futuristic) data.