The nature of dark matter (DM) is still a mystery that may indicate the necessity for extensions of the Standard Model (SM). Light dark photons (DP) may comprise partially or entirely the observed DM density and existing limits for the DP DM parameter space arise from several cosmological and astrophysical sources. In the present work we investigate DP DM using cosmic transients, specifically fast radio bursts (FRBs). The observed time delay of radio photons with different energies have been used to constrain the photon mass or the Weak Equivalence Principle, for example. Due to the mixing between the visible and the DP, the time delay of photons from these cosmic transients, caused by free electrons in the intergalactic medium, can change and impact those constraints from FRBs. We use five detected FRBs and two associations of FRBs with gamma-ray bursts to investigate the correspondent variation on the time delay caused by the presence of DP DM. The result is virtually independent of the FRB used and this variation is very small, considering the still allowed DP DM parameter space, not jeopardizing current bounds on other contributions of the observed time delay.

暗物质（DM）的性质仍然是一个谜，可能表明需要扩展标准模型（SM）。暗暗光子（DP）可能部分或全部包含观测到的DM密度，而DP DM参数空间的现有限制是由几种宇宙学和天体物理学来源引起的。在当前的工作中，我们研究使用宇宙瞬变，特别是快速无线电脉冲串（FRB）的DP DM。例如，已观察到的具有不同能量的无线电光子的时延已被用于约束光子质量或弱当量原理。由于可见光和DP之​​间的混合，由银河际介质中的自由电子引起的来自这些宇宙瞬态的光子的时间延迟会改变并影响FRB的约束。我们使用五个检测到的FRB和两个带有伽马射线暴的FRB关联来调查由DP DM的存在引起的时间延迟的相应变化。考虑到仍然允许的DP DM参数空间，结果实际上与所使用的FRB无关，并且这种变化很小，不会损害观察到的时延的其他贡献上的电流界限。