From an interstellar filament to nascent pillars. A Herschel view of molecular ridge transformation in Vela C
P. Tremblin, T. Hill, N. Lo, F. Motte, N. Schneider, E. Audit and the HOBYS KP team
Using the Herschel space observatory in 5 filters of PACS and SPIRE imagers, and comparing these dust continuum emission images with recent molecular line mapping, we investigate the origin of density enhancements in the RCW36 ridge in Vela C relative with the pre-existing filamentary structure and potential disruption by the nearby star cluster. Pillar-like structures are detected at the borders of the ridge and are interpreted as signatures of material accumulation inside the ridge. Our results suggest that RCW36 and its environment are the scene of two mechanisms: (1) the reshape of this interstellar filament by UV ionisation followed by the emergence of pillar-like structures, (2) star formation inside. Comparisons with numerical simulation conducted by our group and Herschel observations of M16 and the Rosette Nebula lead us to conclude that we observe in Vela C an early phase of pillar formation.