  We construct finite time blowup solutions to the parabolic-elliptic
Keller-Segel system $$\partial_t u = \Delta u - \nabla \cdot (u \nabla
\mathcal{K}_u), \quad -\Delta \mathcal{K}_u = u \quad \textup{in}\;\;
\mathbb{R}^d,\; d = 3,4,$$ and derive the final blowup profile $$ u(r,T) \sim
c_d \frac{|\log r|^\frac{d-2}{d}}{r^2} \quad \textup{as}\;\; r \to 0, \;\; c_d
> 0.$$ To our knowledge this provides a new blowup solution for the
Keller-Segel system, rigorously answering a question by Brenner, Constantin,
Kadanoff, Schenkel, and
  Venkataramani (Nonlinearity, 1999).
