We derive new constraint on millicharged dark matter from the multimessenger observation of GW170817. In the neutron star merger event GW170817, the first detection of a gamma-ray burst (GRB) delayed by approximately 1. 7 seconds relative to the gravitational wave emission was observed. Utilizing this delay, we constrain the millicharge parameter of dark matter within the large-scale structure of the Universe. For dark matter mass below 10^{-15 eV, the millicharge parameter ε is constrained to be less than 10^-14, representing the most stringent limits achieved to date.
Zhang et al. (Sun,) studied this question.