Comparison of low-redshift Lyman-α forest observations to hydrodynamical simulations with dark photon dark matter

Recent work has suggested that an additional less than or similar to 6.9 eV per baryon of heating in the intergalactic medium is needed to reconcile hydrodynamical simulations with Lyman-alpha forest absorption line widths at redshift z similar or equal to 0.1. Resonant conversion of dark photon dark matter into low frequency photons is a viable source of such heating. We perform the first hydrodynamical simulations including dark photon heating and show that dark photons with mass m(A') similar to 8 x 10(-14) eV c(-2) and kinetic mixing epsilon similar to 5 x 10(-15) can alleviate the heating excess. A prediction of this model is a nonstandard thermal history for underdense gas at z greater than or similar to 3.