Spatial Decorrelation of Young Stars and Dense Gas as a Probe of the Star Formation-Feedback Cycle in Galaxies
Abstract
The spatial decorrelation of dense molecular gas and young stars observed on ≲1 kpc scales in nearby galaxies indicates rapid dispersal of star-forming regions by stellar feedback. We explore the sensitivity of this decorrelation to different processes controlling the structure of the interstellar medium, the abundance of molecular gas, star formation, and feedback in a suite of simulations of an isolated dwarf galaxy with structural properties similar to NGC 300 that self-consistently model radiative transfer and molecular chemistry. Our fiducial simulation reproduces the magnitude of decorrelation and its scale dependence measured in NGC 300, and we show that this agreement is due to different aspects of feedback, including H2 dissociation, gas heating by the locally variable UV field, early mechanical feedback, and supernovae. In particular, early radiative and mechanical feedback affects the correlation on ≲100 pc scales, while supernovae play a significant role on ≳ 100 pc scales. The correlation is also sensitive to the choice of the local star formation efficiency per free fall time, ϵff, which provides a strong observational constraint on ϵff when the global star formation rate is independent of its value. Finally, we explicitly show that the degree of correlation between the peaks of molecular gas and star formation density is directly related to the distribution of the lifetimes of star-forming regions.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2021
- DOI:
- 10.3847/1538-4357/ac0a77
- arXiv:
- arXiv:2103.13406
- Bibcode:
- 2021ApJ...918...13S
- Keywords:
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- Interstellar medium;
- Interstellar dynamics;
- Star formation;
- Star forming regions;
- Hydrodynamical simulations;
- Radiative transfer simulations;
- Disk galaxies;
- Dwarf galaxies;
- Stellar feedback;
- 847;
- 839;
- 1569;
- 1565;
- 767;
- 1967;
- 391;
- 416;
- 1602;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 21 pages + appendix, 17 figures