ar X iv : a st ro - p h / 03 02 38 3 v 1 1 9 Fe b 20 03 Chemodynamical gas flow cycles and their influence on the chemical evolution of dwarf irregular galaxies
نویسنده
چکیده
Here we investigate an exemplary chemodynamical evolutionary simulation of a dwarf irregular galaxy. By means of this model we demonstrate the existence of three gas mixing cycles: 1) An inner local cycle mixing the metals produced in stars locally, and 2) an outer galactic cycle on which hot gas is driven out of the galaxy by multiple supernovae type II and mixes on a short timescale with the available cold gas. 3) Only a small fraction of the metals leaves the galactic gravitational field and follows the global cycle with the intergalactic matter. The large-scale mixing results in a temporary depletion of supernova ejected metals. We will discuss this delayed recycling and its influence on the chemical evolution, especially on the nitrogen over oxygen ratio which is increased temporarily. These results presented her are also relevant for less sophisticated analytical approaches and chemical evolutionary models of galaxies which have to parameterize the metal loss through outflow.
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