  In the indirect dark matter (DM) detection framework, the DM particles would
produce some signals by self-annihilating and creating standard model products
such as gamma rays, which might be detected by ground-based telescopes. Dwarf
irregular galaxies represent promising targets for the search for DM as they
are assumed to be dark matter dominated systems at all radii. These dwarf
irregular galaxies are rotationally supported with relatively simple kinematics
which lead to small uncertainties on their dark matter distribution profiles.
In 2018, the H.E.S.S. telescopes observed the irregular dwarf galaxy
Wolf-Lundmark-Melotte (WLM) for a live time of 19 hours. These observations are
the very first ones made by an imaging atmospheric Cherenkov telescope toward
this kind of object. We search for a DM signal looking for an excess of gamma
rays over the background in the direction of the WLM galaxy. We present the
first results obtained on the velocity weighted cross section for DM
self-annihilation as a function of DM particle mass.
