Dynamical processes , element mixing and chemodynamical cycles in dwarf galaxies
نویسنده
چکیده
Since the chemical evolution of galaxies seems to differ between morphological types and deviates in many details from the standard scenario the question has to be addressed when, how and to what amount metal-enriched ejecta from Supernovae and Planetary Nebulae polute their environment. Since recent observations of dwarf galaxies show no significant metal abundance gradients throughout the galaxies while enhancement of metals happens in isolated HII regions, an effective mixing process has to be assumed. Chemodynamical evolution models can provide a possible explanation by demonstrating that strong evaporation of gas clouds by hot gas and following condensation leads to an almost perfect mixing of the gas. We focus on the different phases of chemodynamical evolution that are experienced by a representative dwarf irregular galaxy model and present a quantitative analysis of the chemodynamical gas flow cycles.
منابع مشابه
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
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 ...
متن کاملChemical Abundance Ratios and Gas-phase Mixing in Dwarf Galaxy Evolution
Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g. stellar radiation, winds or explosions, or by their environment. While the metallicity depletion in dwarf galaxies can be explained in general by supernova-driven galactic winds, the reason for their low N/O ratios at low O abundance is not yet completel...
متن کاملStar Formation Regulation, Gas Cycles and the Chemical Evolution of Dwarf Irregular Galaxies
Due to their low gravitational energies, dwarf galaxies are greatly exposed to energetical influences from internal and external sources. By means of chemodynamical models we show that their star formation is inherently self-regulated, that peculiar abundance ratios can only be achieved assuming different star-formation episodes and that evaporation of interstellar clouds embedded in a hot phas...
متن کاملEvolution of dwarf-elliptical galaxies
Here we present as an extension to already published models of massive spherical galaxies one-dimensional chemodynamical models of dwarf elliptical galaxies in the mass range between 10 and 10 M and initial density fluctuation of 1σ and 3σ. Because of their vanishing angular momentum the models are restricted to spherical symmetry. Due to this limitation the dynamics of the different components...
متن کاملThe early evolution of tidal dwarf galaxies
Context. Dwarf galaxies can arise from self-gravitating structures emerging from tidal tails. What fraction of the known dwarf galaxies in the Local Universe can have this origin is still a matter of debate. Aims. In our effort to understand the origin and evolution of tidal dwarf galaxies and their correspondence with local objects, the first step is to understand how these galaxies (which are...
متن کامل