Star formation in the massive "starless" infrared dark cloud G0.253+0.016

Abstract

G0.253+0.016 is a remarkable massive infrared dark cloud located within ∼100 pc of the galactic center. With a high mass of 1.3 × 10 5 M⊙, a compact average radius of ∼2.8 pc, and a low dust temperature of 23 K, it has been believed to be a yet starless precursor to a massive Arches-like stellar cluster. We present sensitive JVLA 1.3 and 5.6 cm radio continuum observations that reveal the presence of three compact thermal radio sources projected against this cloud. These radio sources are interpreted as H II regions powered by ∼B0.5 zero-age main sequence stars. We conclude that although G0.253+0.016 does not show evidence of O-type star formation, there are certainly early B-type stars embedded in it. We detect three more sources in the periphery of G0.253+0.016 with non-thermal spectral indices. We suggest that these sources may be related to the galactic center region and deserve further study. © 2013. The American Astronomical Society. All rights reserved.