|
First Stars III
Contact:
|
Poster
Title: Formation of metal-free protogalaxies Author(s): Jarrett L. Johnson Abstract: The formation of the first galaxies is strongly affected by the radiative feedback from the first generations of stars. This feedback is manifested by the heating and ionization of the gas which lies within the H II regions surrounding the first stars, as well as by the photodissociation of molecules within the larger ÒLyman-Werner bubblesÓ that surround these sources. With the deaths of the first stars, the fossil H II regions begin to cool and recombine, and the high electron fraction in these relic H II regions leads to the rapid generation of a high fraction of molecules, both H_2 and HD. This locally high abundance of molecules plays an important role in the subsequent evolution of the primordial gas, as it becomes virialized in more massive dark matter halos in the course of structure formation. Using a ray-tracing method in 3-D hydrodynamics simulations, we self-consistently track the formation of, and radiative feedback from, individual stars in the course of the formation of a protogalaxy. We compute in detail the H II regions of each of these sources, as well as the regions affected by the molecule-dissociating radiation which they emit. We follow the thermal, chemical, and dynamical evolution of the primordial gas, as it becomes incorporated into the protogalaxy.
|
