Questioning a 3.5 keV dark matter emission line
  Context. Recent findings of line emission at 3.5 keV in both individual and
stacked X-ray spectra of galaxy clusters have been speculated to have dark
matter origin. Aims. If the origin is indeed dark matter, the emission line is
expected to be detectable from the Milky Way dark matter halo. Methods. We
perform a line search in public Chandra X-ray observations of the region near
Sgr A*. We derive upper limits on the line emission flux for the 2.0-9.0 keV
energy interval and discuss their potential physical interpretations including
various scenarios of decaying and annihilating dark matter. Results. While find
no clear evidence for its presence, the upper flux limits are not inconsistent
with the recent detections for conservative mass profiles of the Milky Way.
Conclusions. The results depends mildly on the spectral modelling and strongly
on the choice of dark matter profile.
