All quiet on the Western front? New evidence for massive star formation in Sgr C

We summarize here our recent findings from near-infrared spectroscopy and 1 mm line and continuum observations of a recently identified extended green object (EGO) in Sgr C, whose observational characteristics suggest early-stage massive star formation is taking place. Located on the outskirts of the massive evolved Hii region associated with Sgr C in the Western central molecular zone (CMZ), the EGO measures ∼10″ (0.4 pc at 8.5 kpc). We confirm that early-stage star formation is taking place on the periphery of the Sgr C Hii region. The data show clear detections of two protostellar cores and several knots of H2 and Brackett γ emission alongside a previously detected compact radio source. We calculate the cores' joint mass to be ∼103 M⊙, with column densities of 1-2 × 1024 cm−2. The host molecular clouds mass is approximately 105 M⊙. Despite these favorable conditions, the cloud is curiously devoid of any further star formation, making it comparable to other remarkably quiescent clouds, such as G0.253 in the Eastern CMZ.