Metals from star-forming dwarfs: retention or ejection? |
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Authors: | Daniel Kunth Françcois Legrand Guillermo Tenorio-Tagle Sergey Silich J Miguel Mas-Hesse Miguel Cerviño |
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Institution: | (1) Institut d'Astrophysique, 98bis Bld Arago, F-75014, Paris;(2) Instituto N. de Astrofísica Optica y Electrónica, AP 51, 72000 Puebla, Mexico;(3) LAEFF-INTA, POB 50727, E-28080, Madrid, Spain;(4) Observatoire Midi Pyrènées; 14, avenue E. Belin, 31400 Toulouse, France |
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Abstract: | We show evidences that gas outflows occur in starburst galaxies as superbubbles evolve. We then question whether hot gas will
be expelled and enrich the IGM with metals or be retained within the host galaxy. For this purpose we construct three extreme
scenarios of the star formation histories for a sample of dwarf galaxies using either their present metallicity or their luminosity.
The three scenarios imply different mechanical energy input rates, those are compared with theoretical lower limits for the
ejection of processed matter out of host galaxies. The comparison strongly points at the existence of extended gaseous haloes
acting as a barrier that allows these galaxies to retain their metals and enhance their abundance. Our findings strongly point
that continuous star-forming processes, rather than coeval bursts, must contribute to the overall metallicity in our galaxy
sample.
This revised version was published online in September 2006 with corrections to the Cover Date. |
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Keywords: | metals star-forming galaxies superbubbles ISM |
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