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The gravitational wakefield of a molecular cloud in a disk galaxyA molecular cloud (considered as a point macroparticle) represents a clump of increased mass density moving in the disk of a galaxy. Its presence generates a gravitational polarization of the disk, somewhat analogous to the polarization of a dielectric medium by a test charged particle. This means that the cloud travels along with a wakefield (a region of increased mass density) which is the collective response of the stars and gas to the perturbing mass. It can represent many times the mass of the cloud, and emits spiral density waves which propagate away. In terms of statistical mechanics, this wakefield will appear as an increased two-particle correlation function which is the equivalent of the Debye sphere in a plasma - despite the absence here of negative charges. At short distances clouds will thus interact through their own gravitational field amplified by their wakefields, which might thus strongly affect their collisionality. Researchers present a calculation of this wakefield and discuss its importance in the collisional dynamics of molecular clouds.
Document ID
19910004875
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Tagger, M.
(Commissariat a l'Energie Atomique Saclay (France)., United States)
Pellat, R.
(Institut d'Astrophysique Paris (France)., United States)
Sygnet, J. F.
(Institut d'Astrophysique Paris, France)
Date Acquired
September 6, 2013
Publication Date
July 1, 1990
Publication Information
Publication: NASA, Ames Research Center, The Interstellar Medium in External Galaxies: Summaries of Contributed Papers
Subject Category
Astrophysics
Accession Number
91N14188
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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