We consider the boundary value problem
where Ω is a bounded smooth domain in
R2,
λ>0 and
ν is the inner normal derivative at ∂Ω. This problem is equivalent to the stationary Keller–Segel system from chemotaxis.
We establish the existence of a solution uλ which exhibits a sharp boundary layer along the entire boundary ∂Ω as λ→0. These solutions have large mass in the sense that ∫Ωλeuλ∼|logλ|.