Blow-up solutions for the steady state of the Keller-Segel system on Riemann surfaces

Zhengni Hu, Thomas Bartsch, Mohameden Ahmedou

Published 2024-08-31Version 1

We study the following Neumann boundary problem related to the stationary solutions of the Keller-Segel system, a basic model of chemotaxis phenomena: \[ -\Delta_g u +\beta u =\lambda\left(\frac{Ve^u}{\int_{\Sigma} Ve^u d v_g}-\frac{1}{|\Sigma|_g}\right) \text { in } \mathring\Sigma \] with $\partial_{ \nu_g} u=0, \text { on } \partial \Sigma$, where $(\Sigma, g)$ is a compact Riemann surface with the interior $\mathring\Sigma$ and the smooth boundary $\partial \Sigma$. Here, $\lambda, \beta\geq 0$ are non-negative parameters, and $V$ is a smooth non-negative function with a finite zero set. For any given integers $m\geq k\geq 0$, we establish a sufficient condition on $V$ for the existence of a sequence of blow-up solutions as $\lambda$ approaches the critical values $4\pi(m+k)$. Moreover, the study expands to the corresponding singular problem.