Ionizing feedback from massive stars in massive clusters: Fake bubbles and untriggered star formation

TL;DR

This study uses simulations to explore how ionizing radiation from massive stars affects star formation in turbulent molecular clouds, revealing that dense gas shields filaments from erosion and ionized gas fills pre-existing voids.

Contribution

It demonstrates that ionizing feedback from massive stars does not trigger star formation but instead fills existing voids, challenging previous assumptions about feedback effects.

Findings

Ionizing radiation fills pre-existing voids and bubbles.

Dense gas shields star-forming filaments from radiation.

Feedback does not trigger but influences gas distribution.

Abstract

We use Smoothed Particle Hydrodynamics to simulate the formation of a massive (10^6Msun) stellar cluster system formed from the gravitational collapse of a turbulent molecular cloud. We investigate the hierarchical clustering properties of our model system and we study the influence of the photoionizing radiation produced by the system's multiple O-type stars on the evolution of the protocluster. We find that dense gas near the ionizing sources prevents the radiation from eroding the filaments in which most of the star formation occurs and that instead, ionized gas fills pre-existing voids and bubbles originally created by the turbulent velocity field.