Massive stars (>8 M⊙) form ionised (HII) regions that expand into
the surrounding molecular cloud. This expansion strongly modifies the
cloud's structure and associated star formation (SF) history. However,
the way this radiative feedback affects cloud properties and physical
conditions as a function of time and spatial scale is still debated.
Using high-resolution (7 milli-pc for a 30 pc-box) MHD simulations, I
will present the evolution of an isolated 10^4 M⊙ cloud impacted by
radiative feedback under varying ionising star masses, magnetic field
strengths, and including turbulence injection by protostellar jets.
I will discuss how the cloud's structure evolves and how SF rate and
efficiency are affected at multiple scales, showing how feedback
influences the SF properties of the entire cloud, down to individual clumps.
We apply the same techniques as the ones used in observational studies to study the evolution of the clouds’ Kennicutt-Schmidt relation. We find that the presence of radiation initially enhances the local star formation efficiency per free-fall time (εff) in high-density regions of the clouds, while jets decrease it. We show that this effect is primarily governed by their impact on the cloud structure. Furthermore, looking at the temporal variation of the global εff, we speculate that in a sample of real clouds, for which their evolutionary stage is not taken into account, those variations could be enough to blend the effect of feedback, emphasizing the significance of analyzing the relation as a function of column density.
Finally, I will present a comparison with observations and discuss how
observational biases (resolution limits, extinction of the sources and
incomplete sampling of young stellar object ages) could impact the way
we envision the role of feedback on SF.