Bounds on WIMP dark matter from galaxy clusters at low redshift
  The study of the cross-correlation angular power spectrum between
gravitational tracers and electromagnetic signals can be a powerful tool to
constrain Dark Matter (DM) microscopic properties. In this work we correlate
\Fermi\ diffuse \g-ray maps with catalogues of galaxy clusters. To emphasize
the sensitivity to a DM signal, we select clusters at low-redshift $0<z<0.2$
and with large-halo mass $M_{500}>10^{13}M_\odot$. The analysis is performed
with four catalogues in different wavebands, including infrared, optical and
X-rays. No evidence for a DM signal is identified. On the other hand, we derive
competitive bounds: the thermal cross-section is excluded at 95\% C.L. for DM
masses below 20 GeV and annihilation in the $\tau^+-\tau^-$ channel.
