Comparison of the electron density profiles of this work, the reproduced filament in the SLOW mock observation, and the L > 20 Mpc WHIM filaments at z = 0 (Galárraga-Espinosa et al. 2021) in the IllustrisTNG simulation. The uncertainty intervals of this work divide into the (smaller) statistical uncertainty of the data and the (larger) systematic uncertainty including the temperature and metallicity ranges obtained from the spectral analysis and varying the assumptions of the inclination angle and truncation radius of the β-model. However, these uncertainties are not independent of each other.