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The lifecycle of molecular clouds in nearby star-forming disc galaxies

It remains a major challenge to derive a theory of cloud-scale (≲100 pc) star formation and feedback, describing how galaxies convert gas into stars as a function of the galactic environment. Progress has been hampered by a lack of robust empirical constraints on the giant molecular cloud (GMC) life...

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Hauptverfasser: Chevance, Mélanie (VerfasserIn) , Kruijssen, Diederik (VerfasserIn) , Hygate, Alexander P. S. (VerfasserIn) , Schruba, Andreas (VerfasserIn) , Longmore, Steven N (VerfasserIn) , Groves, Brent (VerfasserIn) , Henshaw, Jonathan D. (VerfasserIn) , Herrera, Cinthya N (VerfasserIn) , Hughes, Annie (VerfasserIn) , Jeffreson, Sarah (VerfasserIn) , Lang, Philipp (VerfasserIn) , Leroy, Adam K (VerfasserIn) , Meidt, Sharon E. (VerfasserIn) , Pety, Jérôme (VerfasserIn) , Razza, Alessandro (VerfasserIn) , Rosolowsky, Erik (VerfasserIn) , Schinnerer, Eva (VerfasserIn) , Bigiel, Frank (VerfasserIn) , Blanc, Guillermo A (VerfasserIn) , Emsellem, Eric (VerfasserIn) , Faesi, Christopher M (VerfasserIn) , Glover, Simon (VerfasserIn) , Haydon, Daniel T. (VerfasserIn) , Ho, I-Ting (VerfasserIn) , Kreckel, Kathryn (VerfasserIn) , Lee, Janice C (VerfasserIn) , Liu, Daizhong (VerfasserIn) , Querejeta, Miguel (VerfasserIn) , Saito, Toshiki (VerfasserIn) , Sun, Jiayi (VerfasserIn) , Usero, Antonio (VerfasserIn) , Utomo, Dyas (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 2020
In: Monthly notices of the Royal Astronomical Society
Year: 2020, Jahrgang: 493, Heft: 2, Pages: 2872-2909
ISSN:1365-2966
DOI:10.1093/mnras/stz3525
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1093/mnras/stz3525
Volltext
Verfasserangaben:Mélanie Chevance, JM Diederik Kruijssen, Alexander PS Hygate, Andreas Schruba, Steven N Longmore, Brent Groves, Jonathan D Henshaw, Cinthya N Herrera, Annie Hughes, Sarah MR Jeffreson, Philipp Lang, Adam K Leroy, Sharon E Meidt, Jérôme Pety, Alessandro Razza, Erik Rosolowsky, Eva Schinnerer, Frank Bigiel, Guillermo A Blanc, Eric Emsellem, Christopher M Faesi, Simon CO Glover, Daniel T Haydon, I-Ting Ho, Kathryn Kreckel, Janice C Lee, Daizhong Liu, Miguel Querejeta, Toshiki Saito, Jiayi Sun, Antonio Usero and Dyas Utomo
Beschreibung
Zusammenfassung:It remains a major challenge to derive a theory of cloud-scale (≲100 pc) star formation and feedback, describing how galaxies convert gas into stars as a function of the galactic environment. Progress has been hampered by a lack of robust empirical constraints on the giant molecular cloud (GMC) lifecycle. We address this problem by systematically applying a new statistical method for measuring the evolutionary timeline of the GMC lifecycle, star formation, and feedback to a sample of nine nearby disc galaxies, observed as part of the PHANGS-ALMA survey. We measure the spatially resolved (∼100 pc) CO-to-H α flux ratio and find a universal de-correlation between molecular gas and young stars on GMC scales, allowing us to quantify the underlying evolutionary timeline. GMC lifetimes are short, typically $10\!-\!30\,{\rm Myr}$, and exhibit environmental variation, between and within galaxies. At kpc-scale molecular gas surface densities ΣH2≥8M⊙pc−2, the GMC lifetime correlates with time-scales for galactic dynamical processes, whereas at ΣH2≤8M⊙pc−2 GMCs decouple from galactic dynamics and live for an internal dynamical time-scale. After a long inert phase without massive star formation traced by H α (75-90 per cent of the cloud lifetime), GMCs disperse within just 1-5 Myr once massive stars emerge. The dispersal is most likely due to early stellar feedback, causing GMCs to achieve integrated star formation efficiencies of 4-10 per cent. These results show that galactic star formation is governed by cloud-scale, environmentally dependent, dynamical processes driving rapid evolutionary cycling. GMCs and H ii regions are the fundamental units undergoing these lifecycles, with mean separations of 100−300 pc in star-forming discs. Future work should characterize the multiscale physics and mass flows driving these lifecycles.
Beschreibung:Advance access publication 2019 December 19
Gesehen am 15.04.2021
Beschreibung:Online Resource
ISSN:1365-2966
DOI:10.1093/mnras/stz3525

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