The lifecycle of molecular clouds in nearby star-forming disc galaxies - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2020

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

Mélanie Chevance
J. M. Diederik Kruijssen
  • Fonction : Auteur
Alexander P. S. Hygate
  • Fonction : Auteur
Andreas Schruba
  • Fonction : Auteur
Steven N. Longmore
  • Fonction : Auteur
Brent Groves
Jonathan D. Henshaw
  • Fonction : Auteur
Cinthya N. Herrera
  • Fonction : Auteur
Sarah M. R. Jeffreson
  • Fonction : Auteur
Philipp Lang
  • Fonction : Auteur
Adam K. Leroy
  • Fonction : Auteur
Sharon E. Meidt
  • Fonction : Auteur
Jérôme Pety
Alessandro Razza
Erik Rosolowsky
Eva Schinnerer
Frank Bigiel
Guillermo A. Blanc
  • Fonction : Auteur
Christopher M. Faesi
  • Fonction : Auteur
Simon C. O. Glover
  • Fonction : Auteur
Daniel T. Haydon
  • Fonction : Auteur
I. -Ting Ho
  • Fonction : Auteur
Kathryn Kreckel
Janice C. Lee
  • Fonction : Auteur
Daizhong Liu
Miguel Querejeta
Toshiki Saito
Jiayi Sun
Antonio Usero
Dyas Utomo

Résumé

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 Myr, and exhibit environmental variation, between and within galaxies. At kpc-scale molecular gas surface densities Σ _H_2≥8 M_⊙ pc^{-2}, the GMC lifetime correlates with time-scales for galactic dynamical processes, whereas at Σ _H_2≤8 M_⊙ 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.
Fichier principal
Vignette du fichier
stz3525.pdf (7.23 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

insu-03673154 , version 1 (20-05-2022)

Identifiants

Citer

Mélanie Chevance, J. M. Diederik Kruijssen, Alexander P. S. Hygate, Andreas Schruba, Steven N. Longmore, et al.. The lifecycle of molecular clouds in nearby star-forming disc galaxies. Monthly Notices of the Royal Astronomical Society, 2020, 493, pp.2872-2909. ⟨10.1093/mnras/stz3525⟩. ⟨insu-03673154⟩
26 Consultations
18 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More