Massive SFR beyond the solar circle

We utilise data from the recently available SASSy 850um survey to identify massive star forming clumps in the outer Galaxy (R_GC_>8.5kpc) and cross-match with infrared and radio data of known UC HII regions from the RMS database. For the inner Galaxy sample (R_GC_<8.5kpc), we adopt the compact HII regions from previous works that used similar methods to cross match ATLASGAL with either CORNISH or RMS, depending on the location within the Galactic plane.

We present a new UC HII region catalogue that more than doubles the original sample size of previous work, totalling 536 embedded HII regions and 445 host clumps. We examine the distance independent values of N_Ly_/M and L_bol_/M as proxies for massive star formation efficiency and overall star formation efficiency, respectively. We find a significant trend showing that L_bol_/M decreases with increasing RGC, suggesting that the overall star formation per unit mass is less in the outer Galaxy.