Multiple peak aggregations for the Keller-Segel system
  In this paper we derive matched asymptotic expansions for a solution of the Keller-Segel system in two space dimensions for which the amount of mass aggregation is $8\pi N$, where $N=1,2,3,...$ Previously available asymptotics had been computed only for the case in which N=1. 
Yukihiro Seki, Yoshie Sugiyama, and Juan J. L. Vel\'azquez
math.AP