The inception of star cluster formation revealed by [C ii] emission around an Infrared Dark Cloud
Journal article, 2018

We present SOFIA-upGREAT observations of [C ii] emission of Infrared Dark Cloud (IRDC) G035.39-00.33, designed to trace its atomic gas envelope and thus test models of the origins of such clouds. Several velocity components of [C ii] emission are detected, tracing structures that are at a wide range of distances in the Galactic plane. We find a main component that is likely associated with the IRDC and its immediate surroundings. This strongest emission component has a velocity similar to that of the 13CO(2-1) emission of the IRDC, but offset by ∼3 km s-1 and with a larger velocity width of ∼9 km s-1. The spatial distribution of the [C ii] emission of this component is also offset predominantly to one side of the dense filamentary structure of the IRDC. The C ii column density is estimated to be of the order of ∼1017-1018 cm-2. We compare these results to the [C ii] emission from numerical simulations of magnetized, dense gas filaments formed from giant molecular cloud (GMC) collisions, finding similar spatial and kinematic offsets. These observations and modellingof [C ii] add further to the evidence that IRDC G035.39-00.33 has been formed by a process of GMC-GMC collision, which may thus be an important mechanism for initiating star cluster formation.

radiative transfer

ISM: clouds

ISM: kinematics and dynamics


T. G. Bisbas

University of Virginia

Max Planck Society

Jonathan Tan

University of Virginia

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

T. Csengeri

Max Planck Society

Benjamin Wu

National Astronomical Observatory of Japan

Wanggi Lim

NASA Ames Research Center

P. Caselli

Max Planck Society

R. Güsten

Max Planck Society

Oliver Ricken

Max Planck Society

D. Riquelme

Max Planck Society

Monthly Notices of the Royal Astronomical Society: Letters

17453925 (ISSN) 17453933 (eISSN)

Vol. 478 1 L54-L59

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Fusion, Plasma and Space Physics



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