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.
Författare
Jonathan D. Henshaw
Max-Planck-Gesellschaft
J. M. D. Kruijssen
Astronomisches Rechen-Institut Heidelberg
S. Longmore
Liverpool John Moores University
Manuel Riener
Max-Planck-Gesellschaft
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
R. S. Klessen
Universität Heidelberg
E. Schinnerer
Max-Planck-Gesellschaft
Andreas Schruba
Max-Planck-Gesellschaft
H. Beuther
Max-Planck-Gesellschaft
F. Bigiell
Universität Bonn
Guillermo A. Blanc
Carnegie Observatories
Universidad de Chile (UCH)
Eric Emsellem
European Southern Observatory (ESO)
CRAL Le Centre de Recherche Astronomique de Lyon
T. Henning
Max-Planck-Gesellschaft
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. 4 11 1064-1071Ämneskategorier
Astronomi, astrofysik och kosmologi
Strömningsmekanik och akustik
Fusion, plasma och rymdfysik
DOI
10.1038/s41550-020-1126-z