Best-fitting SED models per FXT. Top panels: Best-fitting SED model obtained from BAGPIPES (Carnall et al. 2018) for each source #1 associated with FXTs 16, 18, 19, 21 and 22, and the relative transmission functions of the different filters used in the fitting process (colored curves). The 16th to 84th percentile range for the posterior spectrum (shaded gray region) and predicted photometry points (orange markers) are shown. The actual photometric data and their uncertainties are given by the blue markers. Bottom panels: Posterior distributions for the five fitted parameters (star-formation rate, age, galaxy stellar mass, metallicity, and redshift) are shown. The 16th, 50th, and 84th percentile posterior values are indicated by the vertical dashed black lines.