# # Pb with np.loadtxt(): when there is only one index in the file, the resulting array has a shape = (), but size still equal to 1. Reshaping it puts it with shape = (1,) and hence it can be normally manipulated then
# 1: sets the PSDs from official GWTC-1 open PSD data; 2: computes PSDs using Welch methods from gwosc open strain data; 3: uses bilby's analytical pre-stored PSD files.