The Organization of Cloud-scale Gas Density Structure: High-resolution CO versus 3.6 μm Brightness Contrasts in Nearby Galaxies - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue The Astrophysical Journal Année : 2021

The Organization of Cloud-scale Gas Density Structure: High-resolution CO versus 3.6 μm Brightness Contrasts in Nearby Galaxies

Sharon E. Meidt
  • Fonction : Auteur
Adam K. Leroy
  • Fonction : Auteur
Miguel Querejeta
Eva Schinnerer
Jiayi Sun
Arjen van Der Wel
  • Fonction : Auteur
Jonathan Henshaw
J. M. Diederik Kruijssen
  • Fonction : Auteur
Erik Rosolowsky
Andreas Schruba
  • Fonction : Auteur
Ashley Barnes
Frank Bigiel
Guillermo A. Blanc
  • Fonction : Auteur
Melanie Chevance
  • Fonction : Auteur
Yixian Cao
Daniel A. Dale
  • Fonction : Auteur
Christopher Faesi
Simon C. O. Glover
  • Fonction : Auteur
Kathryn Grasha
Brent Groves
Ralf S. Klessen
  • Fonction : Auteur
Kathryn Kreckel
Daizhong Liu
Hsi-An Pan
Toshiki Saito
Antonio Usero
Elizabeth Watkins
Thomas G. Williams
  • Fonction : Auteur

Résumé

In this paper we examine the factors that shape the distribution of molecular gas surface densities on the 150 pc scale across 67 morphologically diverse star-forming galaxies in the PHANGS-ALMA CO (2-1) survey. Dividing each galaxy into radial bins, we measure molecular gas surface density contrasts, defined here as the ratio between a fixed high percentile of the CO distribution and a fixed reference level in each bin. This reference level captures the level of the faint CO floor that extends between bright filamentary features, while the intensity level of the higher percentile probes the structures visually associated with bright, dense interstellar medium features like spiral arms, bars, and filaments. We compare these contrasts to matched percentile-based measurements of the 3.6 μm emission measured using Spitzer/IRAC imaging, which trace the underlying stellar mass density. We find that the logarithms of CO contrasts on 150 pc scales are 3-4 times larger than, and positively correlated with, the logarithms of 3.6 μm contrasts probing smooth nonaxisymmetric stellar bar and spiral structures. The correlation appears steeper than linear, consistent with the compression of gas as it flows supersonically in response to large-scale stellar structures, even in the presence of weak or flocculent spiral arms. Stellar dynamical features appear to play an important role in setting the cloud-scale gas density in our galaxies, with gas self-gravity perhaps playing a weaker role in setting the 150 pc scale distribution of gas densities.
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hal-03585905 , version 1 (27-03-2024)

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Sharon E. Meidt, Adam K. Leroy, Miguel Querejeta, Eva Schinnerer, Jiayi Sun, et al.. The Organization of Cloud-scale Gas Density Structure: High-resolution CO versus 3.6 μm Brightness Contrasts in Nearby Galaxies. The Astrophysical Journal, 2021, 913, 16 pp. ⟨10.3847/1538-4357/abf35b⟩. ⟨hal-03585905⟩
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