Benoit Côté, Hugo Martel, Laurent Drissen, Carmelle Robert
We present a model to self-consistently describe the joint evolution of
starburst galaxies and the galactic wind resulting from this evolution. We
combine the population synthesis code Starburst99 with a semi-analytical model
of galactic outflows and a model for the distribution and abundances of
chemical elements inside the outflows. Starting with a galaxy mass, formation
redshift, and adopting a particular form for the star formation rate, we
describe the evolution of the stellar populations in the galaxy, the evolution
of the metallicity and chemical composition of the interstellar medium (ISM),
the propagation of the galactic wind, and the metal-enrichment of the
intergalactic medium (IGM). In this paper, we study the properties of the
model, by varying the mass of the galaxy, the star formation rate, and the
efficiency of star formation. Our main results are the following: (1) For a
given star formation efficiency f*, a more extended period of active star
formation tends to produce a galactic wind that reaches a larger extent. If f*
is sufficiently large, the energy deposited by the stars completely expels the
ISM. Eventually, the ISM is being replenished by mass loss from supernovae and
stellar winds. (2) For galaxies with masses above 10^11 Msun, the material
ejected in the IGM always falls back onto the galaxy. Hence lower-mass galaxies
are the ones responsible for enriching the IGM. (3) Stellar winds play a minor
role in the dynamical evolution of the galactic wind, because their energy
input is small compared to supernovae. However, they contribute significantly
to the chemical composition of the galactic wind. We conclude that the history
of the ISM enrichment plays a determinant role in the chemical composition and
extent of the galactic wind, and therefore its ability to enrich the IGM.
View original:
http://arxiv.org/abs/1112.2182
No comments:
Post a Comment