The Origin of Metals in the Circumgalactic and the Intergalactic Medium

Sijing Shen

University of California, Santa Cruz

The distribution and evolution of metals in the circumgalactic medium (CGM) and the intergalactic medium (IGM) are “fossil records” of the interactions between galaxies and their surrounding gas. In this talk, I will first discuss the modeling of metal enrichment in cosmological simulations, focusing on the treatment of supernova-driven outflows, metal cooling and metal mixing due to turbulence. Then I will present a detailed study of the metal-enriched CGM of a massive galaxy at z = 3, using results from a series of cosmological hydrodynamic “zoom-in” simulations. Our study shows that: 1) metal enriched gas extends as far as 200 physical kpc (more than 4 virial radii) from the host galaxy center; 2) metals located farther away from the host are generally produced at an earlier epoch; 3) there are three sources of heavy elements: the main host, its satellite progenitors and its dwarf companions, and the latter two contribute significantly to the metal budget. Finally, I will present a comparison between simulations and recent observations on spatial distribution of metal absorbers (such as C IV, C II, Si IV and Si II) around Lyman break galaxies at z = 2-3, and discuss the effects of feedback models and metal cooling.

Date: Jeudi, le 15 décembre 2011
Heure: 11:30
Lieu: Université de Montréal
  Pavillon Roger-Gaudry, local D-460
Contact: Marie-Eve Naud