  Recently, the Event Horizon Telescope collaboration has reported the first
image of the supermassive black hole Sagittarius in the Galactic Center. We
attempt to test the validity of the no-hair theorem of black holes using this
new shadow observation. Considering the Einstein-Maxwell-klein-Gordon theory
with a minimally-coupled scalar field, we find that our numerical result is
consistent with the prediction of the no-hair theorem. However, we can not rule
out the possibility that black holes with scalar hair may exist in some special
cases.
