Oral Presentation
Effect of recombination radiation in the formation of first stars
Presenter: Satoshi Tanaka (Center for Computational Sciences, University of Tsukuba)
The strong radiation of the first generation of stars (first stars) affect the formation of other stars in their vicinity. The formation of secondary stars is regulated with strong photo-heating effect in a certain condition, and also is promoted in anther condition because the radiation of first stars promotes the formation hydrogen molecules as a coolant of primordial gas. In this work, we investigate the formation criteria of secondary star formation in the vicinity of first stars using radiation hydrodynamic simulations, especially focusing the effect of recombination radiation which has not been taken into account in the previous studies. We present the radiation hydrodynamic simulations performed with ``ARGOT'' code which is able to compute the radiation transfer both of diffuse radiation (recombination radiation) and radiation from point sources (stars) in a reasonable computational performance with the aid of GPUs. We find that the recombination radiation yields significant increase of free electrons and thus promote the formation of hydrogen molecules at the ionization front, which leads to effective shielding of Lyman-Werner photons. These results shows that the radiation of first stars affects the formation of secondary stars in a more positive manner than estimated in the previous studies.
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