Filaments, Ridges and Striations in star-forming regions as revealed by Herschel
Motte, Didelon, Bontemps, and the HOBYS consortium
The Herschel HOBYS key program targets burgeoning young stellar objects and their natal environments. Filamentary structures have been identified in high- (Hill et al, 2011) and low-mass star-forming regions (Arzoumanian et al, 2011). The presence of embedded cores in these filaments suggests that they are universal birth sites for star formation. HOBYS regions also display dominating, clearly distinct, high-column density structures, called "ridges". Ridges have a column density consistent with theoretical predictions of high mass star formation, and may suggest a threshold between high- and low-mass star forming sites. High mass stars appear to preferentially form in ridges. HOBYS regions also have capillary-like striations perpendicular to filaments, which are likely their feeding source. I will present examples and an analysis of filaments, ridges and striations seen in HOBYS region and discuss their role in the formation of low-, intermediate- and high-mass star formation.