4.7 Article

Towards a multitracer timeline of star formation in the LMC - II. The formation and destruction of molecular clouds

Journal

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 516, Issue 3, Pages 4025-4042

Publisher

OXFORD UNIV PRESS
DOI: 10.1093/mnras/stac2467

Keywords

stars: formation; ISM: clouds; ISM: evolution; H II regions; galaxies: evolution; Magellanic Clouds

Funding

  1. Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) [138713538 -SFB 881]
  2. DFG through the DFG Sachbeihilfe [KR4801/2-1]
  3. DFG through an Emmy Noether Research Group [CH2137/1-1, KR4801/1-1]
  4. European Research Council (ERC) under the European Union [714907]

Ask authors/readers for more resources

This paper aims to study the lifecycle of molecular clouds in the Large Magellanic Cloud (LMC) and determines their lifetime to be around 11.8 million years. The study finds that molecular clouds in the LMC are decoupled from galactic dynamics and have short lifetimes regulated by internal processes, while atomic clouds are correlated with galactic dynamical timescales.
The time-scales associated with various stages of the star formation process represent major unknowns in our understanding of galactic evolution, as well as of star and planet formation. This is the second paper in a series aiming to establish a multitracer timeline of star formation in the Large Magellanic Cloud (LMC), focusing on the life cycle of molecular clouds. We use a statistical method to determine a molecular cloud lifetime in the LMC of t(CO) = 11.8(-2.2)(+2.7) Myr. This short time-scale is similar to the cloud dynamical time, and suggests that molecular clouds in the LMC are largely decoupled from the effects of galactic dynamics and have lifetimes set by internal processes. This provides a clear contrast to atomic clouds in the LMC, of which the lifetimes are correlated with galactic dynamical time-scales. We additionally derive the time-scale for which molecular clouds and H II regions co-exist as t(fb) = 1.2(-0.2)(+0.3) Myr, implying an average feedback front expansion velocity of 12 km s(-1), consistent with expansion velocities of H II regions in the LMC observed directly using optical spectroscopy. Taken together, these results imply that the molecular cloud life cycle in the LMC proceeds rapidly and is regulated by internal dynamics and stellar feedback. We conclude by discussing our measurements in the context of previous work in the literature, which reported considerably longer lifetimes for molecular clouds in the LMC, and find that these previous findings resulted from a subjective choice in timeline calibration that is avoided by our statistical methodology.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available