SEDIGISM-ATLASGAL: Dense gas fraction and star formation efficiency across the Galactic disc
Journal article, 2021

By combining two surveys covering a large fraction of the molecular material in the Galactic disc, we investigate the role spiral arms play in the star formation process. We have matched clumps identified by APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) with their parental giant molecular clouds (GMCs) as identified by SEDIGISM, and use these GMC masses, the bolometric luminosities, and integrated clump masses obtained in a concurrent paper to estimate the dense gas fractions (DGFgmc = ΣMclump/Mgmc) and the instantaneous star formation efficiencies (i.e. SFEgmc = ΣLclump/Mgmc). We find that the molecular material associated with ATLASGAL clumps is concentrated in the spiral arms (∼60 per cent found within ±10 km s-1 of an arm).We have searched for variations in the values of these physical parameters with respect to their proximity to the spiral arms, but find no evidence for any enhancement that might be attributable to the spiral arms. The combined results from a number of similar studies based on different surveys indicate that, while spiral-arm location plays a role in cloud formation and HI to H2 conversion, the subsequent star formation processes appear to depend more on local environment effects. This leads us to conclude that the enhanced star formation activity seen towards the spiral arms is the result of source crowding rather than the consequence of any physical process.

Stars: Formation

Galaxy: Structure

Submillimetre: ISM

ISM: Clouds

Galaxy: Kinematics and dynamics



J. S. Urquhart

University Of Kent

C. Figura

Wartburg College

J. R. Cross

University Of Kent

M. Wells

University Of Kent

T. J.T. Moore

Liverpool John Moores University

D. J. Eden

Liverpool John Moores University

S. E. Ragan

Cardiff University

A. R. Pettitt

Hokkaido University

A. Duarte-Cabral

Cardiff University

D. Colombo

Max Planck Society

F. Schuller

Max Planck Society

Astrophysikalisches Institut Potsdam

T. Csengeri

University of Bordeaux

M. Mattern

Max Planck Society

University Paris-Saclay

H. Beuther

Max Planck Society

K. M. Menten

Max Planck Society

F. Wyrowski

Max Planck Society

L. D. Anderson

West Virginia University

P. J. Barnes

Space Science Institute

M. Beltrán

Arcetri Astrophysical Observatory

S. J. Billington

University Of Kent

Leonardo Bronfman

University of Chile (UCH)

A. Giannetti

Istituto di Radioastronomia

Jouni Kainulainen

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

J. Kauffmann

Massachusetts Institute of Technology (MIT)

M. Y. Lee

Korea Astronomy and Space Science Institute

S. Leurini

INAF Osservatorio Astronomico di Cagliari

S. N.X. Medina

Max Planck Society

F.M. Montenegro-Montes

European Southern Observatory Santiago

Manuel Riener

Max Planck Society

Andrew Rigby

Cardiff University

A. Sanchez-Monge

University of Cologne

P. Schilke

University of Cologne

E. Schisano

Istituto nazionale di astrofisica (INAF)

A. Traficante

Istituto nazionale di astrofisica (INAF)

M. Wienen

University of Exeter

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 500 3 3050-3063

Subject Categories

Astronomy, Astrophysics and Cosmology

Chemical Process Engineering

Other Chemistry Topics



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