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Ward, JL, Diederik Kruijssen, JM, Chevance, M, Kim, J and Longmore, SN (2022) Towards a multitracer timeline of star formation in the LMC - II. The formation and destruction of molecular clouds. Monthly Notices of the Royal Astronomical Society, 516 (3). pp. 4025-4042. ISSN 0035-8711
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Towards a multitracer timeline of star formation in the LMC - II. The formation and destruction of molecular clouds.pdf - Published Version Download (2MB) | Preview |
Abstract
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 tCO=11.8 +2.7-2.2 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 tfb=1.2 +0.3-0.2 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.
| Item Type: | Article |
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| Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2022 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
| Uncontrolled Keywords: | 0201 Astronomical and Space Sciences; Astronomy & Astrophysics |
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
| Divisions: | Astrophysics Research Institute |
| Publisher: | Oxford University Press (OUP) |
| SWORD Depositor: | A Symplectic |
| Date Deposited: | 16 Mar 2023 15:30 |
| Last Modified: | 16 Mar 2023 15:30 |
| DOI or ID number: | 10.1093/mnras/stac2467 |
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/19127 |
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