  We prove that for any graph $G$ of maximum degree at most $\Delta$, the zeros
of its chromatic polynomial $\chi_G(z)$ (in $\mathbb{C}$) lie outside the disk
of radius $5.02 \Delta$ centered at $0$. This improves on the previously best
known bound of approximately $6.91\Delta$.
  In the case of graphs of high girth we can improve this. We prove that for
every $g$ there is a constant $K_g$ such that for any graph $G$ of maximum
degree at most $\Delta$ and girth at least $g$, the zeros of its chromatic
polynomial $\chi_G(z)$ lie outside the disk of radius $K_g \Delta$ centered at
$0$ where $K_g \to 1 + e \approx 3.72$ as $g \to \infty$.
  Finally, we give improved bounds on the Fisher zeros of the partition
function of the Ising model.
