Dense molecular gas in Herschel/EPoS clumps - Tracing the onset of higher-mass star formation
O. Krause, H. Beuther, S. Ragan, T. Vasyunina, Th. Henning
The Herschel satellite has brought vast progress to our knowledge about the earliest stages of star formation due to its superior spatial resolution and sensitivity. Within our Herschel Key Project EPoS we investigate the 70-500 micron emission (and absorption) of a sample of 45 higher-mass star-forming clumps, mostly comprising infrared dark clouds. Here, we will show the connection between the far-infrared (FIR) appearance of these objects, governed by the dust, and the properties of their dense molecular gas content. For this, we have conducted a larger complementary program using IRAM-30m, Mopra, and Parkes. We show results especially illuminating the conditions at the onset of higher-mass star formation. We trace very early outflow activity and relate it to the embedded population of FIR compact sources, while we also identify candidates for converging gas flows. Furthermore, we demonstrate how an integrated picture based on FIR and line data can lead to advances in chemical modelling of such clumps.