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Molecular line signatures of cloud-cloud collisions

Priestley, F. D. and Whitworth, A. P. 2021. Molecular line signatures of cloud-cloud collisions. Monthly Notices of the Royal Astronomical Society 506 (1) , 775–780. 10.1093/mnras/stab1777

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Abstract

Collisions between interstellar gas clouds are potentially an important mechanism for triggering star formation. This is because they are able to rapidly generate large masses of dense gas. Observationally, cloud collisions are often identified in position–velocity (PV) space through bridging features between intensity peaks, usually of CO emission. Using a combination of hydrodynamical simulations, time-dependent chemistry, and radiative transfer, we produce synthetic molecular line observations of overlapping clouds that are genuinely colliding, and overlapping clouds that are just chance superpositions. Molecules tracing denser material than CO, such as NH3 and HCN, reach peak intensity ratios of 0.5 and 0.2 with respect to CO in the ‘bridging feature’ region of PV space for genuinely colliding clouds. For overlapping clouds that are just chance superpositions, the peak NH3 and HCN intensities are co-located with the CO intensity peaks. This represents a way of confirming cloud collisions observationally and distinguishing them from chance alignments of unrelated material.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: Royal Astronomical Society
ISSN: 0035-8711
Date of First Compliant Deposit: 22 July 2021
Date of Acceptance: 14 June 2021
Last Modified: 22 Jul 2021 08:45
URI: https://orca.cardiff.ac.uk/id/eprint/142684

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