Turbulence Sets the Initial Conditions for Star Formation in High-pressure Environments

Author(s)

J. M. Rathborne, S. N. Longmore, J. M. Jackson, J. M. D. Kruijssen, J. F. Alves, J. Bally, N. Bastian, Y. Contreras, J. B. Foster, G. Garay, L. Testi, A. J. Walsh

Abstract

Despite the simplicity of theoretical models of supersonically

turbulent, isothermal media, their predictions successfully match the

observed gas structure and star formation activity within low-pressure

(P/k <105 K cm–3) molecular clouds in

the solar neighborhood. However, it is unknown whether or not these

theories extend to clouds in high-pressure (P/k > 107 K

cm–3) environments, like those in the Galaxy's inner

200 pc central molecular zone (CMZ) and in the early universe. Here, we

present Atacama Large Millimeter/submillimeter Array 3 mm dust continuum

emission within a cloud, G0.253+0.016, which is immersed in the

high-pressure environment of the CMZ. While the log-normal shape and

dispersion of its column density probability distribution function (PDF)

are strikingly similar to those of solar neighborhood clouds, there is

one important quantitative difference: its mean column density is one to

two orders of magnitude higher. Both the similarity and difference in

the PDF compared to those derived from solar neighborhood clouds match

predictions of turbulent cloud models given the high-pressure

environment of the CMZ. The PDF shows a small deviation from log-normal

at high column densities confirming the youth of G0.253+0.016. Its lack

of star formation is consistent with the theoretically predicted,

environmentally dependent volume density threshold for star formation

which is orders of magnitude higher than that derived for solar

neighborhood clouds. Our results provide the first empirical evidence

that the current theoretical understanding of molecular cloud structure

derived from the solar neighborhood also holds in high-pressure

environments. We therefore suggest that these theories may be applicable

to understand star formation in the early universe.

Organisation(s)

Department of Astrophysics

External organisation(s)

INAF - Osservatorio Astrofisico di Arcetri, Boston University, Yale University, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Liverpool John Moores University (LJMU), Max-Planck-Institut für Astrophysik, University of Colorado, Boulder, Universidad de Chile, European Southern Observatory (Germany), Excellence Cluster Universe, Curtin University

Journal

The Astrophysical journal Letters

Volume

795

No. of pages

ISSN

2041-8205

DOI

https://doi.org/10.1088/2041-8205/795/2/L25

Publication date

11-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/2d1702ce-ff53-49c8-acd8-208a0aab50f5