2019MNRAS.482.5349R

The central molecular zone (CMZ) spans the inner ∼450 pc (∼3°) of our Galaxy. This region is defined by its enhanced molecular emission and contains 5 per cent of the entire Galaxy's molecular gas mass. However, the number of detected star-forming sites towards the CMZ may be low for the amount of molecular gas that is present, and improved surveys of star formation indicators can help clarify this. With the Karl G. Jansky Very Large Array (VLA), we conducted a blind survey of 6.7 GHz methanol (CH₃OH) masers spanning the inner 3° x 40 arcmin (450 pc x 100 pc) of the Galaxy. We detected 43 CH₃OH masers towards 28 locations, ∼16 of which are new detections. The velocities of most of these masers are consistent with being located within the CMZ. A majority of the detected CH₃OH masers are distributed towards positive Galactic longitudes, similar to two-thirds of the molecular gas mass distributed at positive Galactic longitudes. The 6.7 GHz CH₃OH maser is an exclusive indicator of high-mass (>8M_☉) star formation, with new detections indicating sites of massive star formation in the CMZ.