Massive stars in the Sagittarius Dwarf Irregular Galaxy
  Low metallicity massive stars hold the key to interpret numerous processes in
the past Universe including re-ionization, starburst galaxies, high-redshift
supernovae and GRBs. The Sagittarius Dwarf Irregular Galaxy (SagDIG,
12+log(O/H)=7.37) represents an important landmark in the quest for analogues
accessible with 10-m class telescopes. This paper presents low-resolution
spectroscopy executed with the Gran Telescopio Canarias that confirms that
SagDIG hosts massive stars. The observations unveiled three OBA-type stars and
one red supergiant candidate. Pending confirmation from high-resolution
follow-up studies, these could be the most metal-poor massive stars of the
Local Group.
