Oral Presentation
The effect of photoionising feedback on star formation in isolated and colliding turbulent clouds
Presenter: Kazuhiro Shima (Hokkaido University)
Much speculation surrounds the role of collisions between the Giant Molecular Clouds (GMCs). If the collisions can be interpreted as compressive driving of turbulence, then we expect an enhanced star formation. Observation and simulations now suggest cloud-cloud collisions (CCCs) cloud explain the formation of our most massive stars and super star clusters. We use 3D radiation-hydrodynamical simulations and investigate star formation occurring in idealised giant molecular clouds, comparing structures that evolve in isolation versus those undergoing a collision. Two different collision speeds are investigated and the impact of photoionising radiation from the stars is determined. We find that a colliding system leads to more massive star formation both with and without the addition of feedback, raising overall star formation efficiencies (SFE) by a factor of 10 and steepening the high-mass end of the stellar mass function. This rise in SFE is due to increased turbulent compression during the cloud collision. While feedback can both promote and hinder star formation in the isolated system, it increases the SFE by approximately 1.5 times in the colliding case when the thermal speed of the resulting HII regions matches the shock propagation speed in the collision.
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