  In this paper, we propose and study a stochastic aggregation-diffusion
equation of the Keller-Segel (KS) type for modeling the chemotaxis in
dimensions $d=2,3$. Unlike the classical deterministic KS system, which only
allows for idiosyncratic noises, the stochastic KS equation is derived from an
interacting particle system subject to both idiosyncratic and common noises.
Both the unique existence of solutions to the stochastic KS equation and the
mean-field limit result are addressed.
