Revised constraints on the photon mass from well-localized fast radio bursts

We constrain the photon mass from well-localized fast radio bursts (FRBs) using Bayes inference method. The probability distributions of dispersion measures (DMs) of host galaxy and intergalactic medium are properly taken into account. The photon mass is tightly constrained from 17 well-localized FRBs in the redshift range 0 < z < 0.66. Assuming that there is no redshift evolution of host DM, the 1 sigma and 2 sigma upper limits of photon mass are constrained to be m(gamma) < 4.8 x 10(-51) kg and m(gamma) < 7.1 x 10(-51) kg, respectively. Monte Carlo simulations show that even enlarging the FRB sample to 200 and extending the redshift range to 0 < z < 3 could not significantly improve the constraining ability on photon mass. This is because of the large uncertainty on the DM of intergalactic medium.