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Journal Articles The Astrophysical journal letters Year : 2020

Molecular Gas Properties on Cloud Scales across the Local Star-forming Galaxy Population

Jiayi Sun
Adam K. Leroy
  • Function : Author
Eva Schinnerer
Erik Rosolowsky
Miguel Querejeta
Andreas Schruba
  • Function : Author
Daizhong Liu
Toshiki Saito
Cinthya N. Herrera
  • Function : Author
Christopher Faesi
Antonio Usero
Jérôme Pety
J. M. Diederik Kruijssen
  • Function : Author
Eve C. Ostriker
  • Function : Author
Frank Bigiel
Guillermo A. Blanc
  • Function : Author
Alberto D. Bolatto
  • Function : Author
Médéric Boquien
Mélanie Chevance
Daniel A. Dale
  • Function : Author
Sinan Deger
Simon C. O. Glover
  • Function : Author
Kathryn Grasha
Brent Groves
Jonathan Henshaw
Maria J. Jimenez-Donaire
  • Function : Author
Jenny J. Kim
  • Function : Author
Ralf S. Klessen
  • Function : Author
Kathryn Kreckel
Janice C. Lee
  • Function : Author
Sharon Meidt
Karin Sandstrom
Amy E. Sardone
  • Function : Author
Dyas Utomo
Thomas G. Williams
  • Function : Author


Using the PHANGS-ALMA CO(2-1) survey, we characterize molecular gas properties on ∼100 pc scales across 102,778 independent sightlines in 70 nearby galaxies. This yields the best synthetic view of molecular gas properties on cloud scales across the local star-forming galaxy population obtained to date. Consistent with previous studies, we observe a wide range of molecular gas surface densities (3.4 dex), velocity dispersions (1.7 dex), and turbulent pressures (6.5 dex) across the galaxies in our sample. Under simplifying assumptions about subresolution gas structure, the inferred virial parameters suggest that the kinetic energy of the molecular gas typically exceeds its self-gravitational binding energy at ∼100 pc scales by a modest factor (1.3 on average). We find that the cloud-scale surface density, velocity dispersion, and turbulent pressure (1) increase toward the inner parts of galaxies, (2) are exceptionally high in the centers of barred galaxies (where the gas also appears less gravitationally bound), and (3) are moderately higher in spiral arms than in inter-arm regions. The galaxy-wide averages of these gas properties also correlate with the integrated stellar mass, star formation rate, and offset from the star-forming main sequence of the host galaxies. These correlations persist even when we exclude regions with extraordinary gas properties in galaxy centers, which contribute significantly to the inter-galaxy variations. Our results provide key empirical constraints on the physical link between molecular cloud populations and their galactic environment.
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Dates and versions

insu-03673125 , version 1 (20-03-2024)



Jiayi Sun, Adam K. Leroy, Eva Schinnerer, Annie Hughes, Erik Rosolowsky, et al.. Molecular Gas Properties on Cloud Scales across the Local Star-forming Galaxy Population. The Astrophysical journal letters, 2020, 901, ⟨10.3847/2041-8213/abb3be⟩. ⟨insu-03673125⟩
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