Multi-scale analysis of the Monoceros OB 1 star-forming region. I. The dense core population

Abstract

Context. Current theories and models attempt to explain star formation scale observational characterisation of an entire molecular complex i necessary to constrain them. We investigate star formation i G202.3+2.5, a ̃10 × 3 pc sub-region of the Monoceros OB1 cloud with complex morphology that harbours interconnected filamentary structures Aims: We aim to connect the evolution of cores and filaments i G202.3+2.5 with the global evolution of the cloud and to identify th engines of the cloud dynamics. Methods: In this first paper, th star formation activity is evaluated by surveying the distributions o dense cores and protostars and their evolutionary state, a characterised using both infrared observations from the Herschel an WISE telescopes and molecular line observations with the IRAM 30 telescope. Results: We find ongoing star formation in the whole cloud, with a local peak in star formation activity around the centre o G202.3+2.5, where a chain of massive cores (10 - 50 M☉) form a massive ridge (≳150 M☉). All evolutionary stages fro starless cores to Class II protostars are found in G202.3+2.5, includin a possibly starless and massive (52 M☉) core, which present a high column density (8 × 1022 cm-2). Conclusions: All the core-scale observables we examined point to a enhanced star formation activity that is centred on the junction betwee the three main branches of the ramified structure of G202.3+2.5. Thi suggests that the increased star formation activity results from th convergence of these branches. To further investigate the origin of thi enhancement, it is now necessary to extend the analysis to larger scale in order to examine the relationship between cores, filaments, and thei environment. We address these points through the analysis of th dynamics of G202.3+2.5 in a joint paper