Ubiquitous velocity fluctuations throughout the molecular interstellar medium
Artikel i vetenskaplig tidskrift, 2020

The density structure of the interstellar medium determines where stars form and release energy, momentum and heavy elements, driving galaxy evolution1–4. Density variations are seeded and amplified by gas motion, but the exact nature of this motion is unknown across spatial scales and galactic environments5. Although dense star-forming gas probably emerges from a combination of instabilities6,7, convergent flows8 and turbulence9, establishing the precise origin is challenging because it requires gas motion to be quantified over many orders of magnitude in spatial scale. Here we measure10–12 the motion of molecular gas in the Milky Way and in nearby galaxy NGC 4321, assembling observations that span a spatial dynamic range 10−1–103 pc. We detect ubiquitous velocity fluctuations across all spatial scales and galactic environments. Statistical analysis of these fluctuations indicates how star-forming gas is assembled. We discover oscillatory gas flows with wavelengths ranging from 0.3–400 pc. These flows are coupled to regularly spaced density enhancements that probably form via gravitational instabilities13,14. We also identify stochastic and scale-free velocity and density fluctuations, consistent with the structure generated in turbulent flows9. Our results demonstrate that the structure of the interstellar medium cannot be considered in isolation. Instead, its formation and evolution are controlled by nested, interdependent flows of matter covering many orders of magnitude in spatial scale.


Jonathan D. Henshaw


J. M. D. Kruijssen

Astronomisches Rechen-Institut Heidelberg

S. Longmore

Liverpool John Moores University

Manuel Riener


Adam K. Leroy

Ohio State University

E. Rosolowsky

University of Alberta

A. Ginsburg

University of Florida

C. Battersby

University of Connecticut

Mélanie Chevance

Astronomisches Rechen-Institut Heidelberg

Sharon E. Meidt

Universiteit Gent

S. C.O. Glover

Universität Heidelberg

A. Hughes

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Universite Paul Sabatier Toulouse III

Jouni Kainulainen

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

R. S. Klessen

Universität Heidelberg

E. Schinnerer


Andreas Schruba


H. Beuther


F. Bigiell

Universität Bonn

Guillermo A. Blanc

Universidad de Chile (UCH)

Carnegie Observatories

Eric Emsellem

CRAL Le Centre de Recherche Astronomique de Lyon

European Southern Observatory (ESO)

T. Henning


Cynthia N. Herrera

Institut de Radioastronomie Millimétrique (IRAM)

Eric W. Koch

University of Alberta

J. Pety

Institut de Radioastronomie Millimétrique (IRAM)

Observatoire de Paris

S. E. Ragan

Cardiff University

Jiayi Sun

Ohio State University

Nature Astronomy

23973366 (eISSN)

Vol. In Press


Astronomi, astrofysik och kosmologi

Strömningsmekanik och akustik

Fusion, plasma och rymdfysik



Mer information

Senast uppdaterat