SiO emission as a probe of cloud-cloud collisions in infrared dark clouds
Artikel i vetenskaplig tidskrift, 2020

Infrared dark clouds (IRDCs) are very dense and highly extincted regions that host the initial conditions of star and stellar cluster formation. It is crucial to study the kinematics and molecular content of IRDCs to test their formation mechanism and ultimately characterize these initial conditions. We have obtained high-sensitivity Silicon Monoxide, SiO(2-1), emission maps towards the six IRDCs, G018.82-00.28, G019.27+00.07, G028.53-00.25, G028.67+00.13, G038.95-00.47, and G053.11+00.05 (cloud A, B, D, E, I, and J, respectively), using the 30-m antenna at the Instituto de Radioastronomia Millimetrica (IRAM30m). We have investigated the SiO spatial distribution and kinematic structure across the six clouds to look for signatures of cloud-cloud collision events that may have formed the IRDCs and triggered star formation within them. Towards clouds A, B, D, I, and J, we detect spatially compact SiO emission with broad-line profiles that are spatially coincident with massive cores. Towards the IRDCs A and I, we report an additional SiO component that shows narrow-line profiles and that is widespread across quiescent regions. Finally, we do not detect any significant SiO emission towards cloud E. We suggest that the broad and compact SiO emission detected towards the clouds is likely associated with ongoing star formation activity within the IRDCs. However, the additional narrow and widespread SiO emission detected towards cloud A and I may have originated from the collision between the IRDCs and flows of molecular gas pushed towards the clouds by nearby H II regions.

H II regions

ISM: clouds

ISM: molecules

ISM: individual objects: G018.82-00.28, G019.27+00.07, G028.53-00.25, G028.67+00.13, G038.95-00.47, G053.11+00.05

ISM: kinematics and dynamics


Giuliana Cosentino

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

I Jimenez-Serra

Centro de Astrobiología (INTA-CSIC)

J. D. Henshaw


P. Caselli


S. Viti

University College London (UCL)

A. T. Barnes

Universität Bonn

Jonathan Tan

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

F. Fontani

INAF Osservatorio Astron Arcetri

B. Wu

National Astronomical Observatory of Japan

Monthly Notices of the Royal Astronomical Society

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

Vol. 499 2 1666-1681


Meteorologi och atmosfärforskning

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik



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