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Blast wave formation of the extended stellar shells surrounding elliptical galaxiesThe existence of stellar shells at large distances from isolated elliptical galaxies is explained in terms of a blast wave associated with an active nucleus phase early in the history of the galaxy. The blast wave sweeps the initial interstellar medium out of the galaxy into an expanding shell which radiatively cools behind its leading shock front. Cooling of the shell following turnoff of the nucleus activity, which keeps the shell photoionized, leads to a brief epoch of star formation which is terminated by heating of the shell from supernovae and UV radiation from massive stars. The stars so formed follow similar, highly radial, bound orbits, moving in phase with each other and spending much of their time near apogalacteum, thus taking on the appearance of a shell. Multiple shells may be produced when conditions allow repeated episodes of shell cooling and supernovae heating to occur in the blast wave.
Document ID
19850049757
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Williams, R. E.
(NASA Ames Research Center Moffett Field, CA; European Southern Observatory, Garching, West Germany; Observatorio Interamerican, Chile)
Christiansen, W. A.
(North Carolina, University Chapel Hill, NC, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1985
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 291
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
85A31908
Distribution Limits
Public
Copyright
Other

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