Universität zu Köln

Bonne, L., Schneider, N., Bontemps, S., Clarke, S. D., Gusdorf, A., Lehmann, A., Steinke, M., Csengeri, T., Kabanovic, S., Simon, R., Buchbender, C. and Guesten, R. (2020). Dense gas formation in the Musca filament due to the dissipation of a supersonic converging flow. Astron. Astrophys., 641. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Observations with the Herschel Space Telescope have established that most star forming gas is organised in filaments, a finding that is supported by numerical simulations of the supersonic interstellar medium (ISM) where dense filamentary structures are ubiquitous. We aim to understand the formation of these dense structures by performing observations covering the (CO)-C-12(4 -> 3), (CO)-C-12(3 -> 2), and various CO(2-1) isotopologue lines of the Musca filament, using the APEX telescope. The observed CO intensities and line ratios cannot be explained by PDR (photodissociation region) emission because of the low ambient far-UV field that is strongly constrained by the non-detections of the [CII] line at 158 mu m and the [OI] line at 63 mu m, observed with the upGREAT receiver on SOFIA, as well as a weak [CI] 609 mu m line detected with APEX. We propose that the observations are consistent with a scenario in which shock excitation gives rise to warm and dense gas close to the highest column density regions in the Musca filament. Using shock models, we find that the CO observations can be consistent with excitation by J-type low-velocity shocks. A qualitative comparison of the observed CO spectra with synthetic observations of dynamic filament formation simulations shows a good agreement with the signature of a filament accretion shock that forms a cold and dense filament from a converging flow. The Musca filament is thus found to be dense molecular post-shock gas. Filament accretion shocks that dissipate the supersonic kinetic energy of converging flows in the ISM may thus play a prominent role in the evolution of cold and dense filamentary structures.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Bonne, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schneider, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bontemps, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Clarke, S. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gusdorf, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lehmann, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Steinke, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Csengeri, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kabanovic, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Simon, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Buchbender, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Guesten, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-321106
DOI:	10.1051/0004-6361/201937104
Journal or Publication Title:	Astron. Astrophys.
Volume:	641
Date:	2020
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MAGNETOHYDRODYNAMIC SHOCK-WAVES; SIO LINE EMISSION; C-II; PHOTODISSOCIATION REGIONS; INTERSTELLAR JETS; THERMAL BALANCE; MOLECULAR CLOUD; DARK-CLOUDS; STAR; (CO)-O-18 Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/32110