Rafael S. de Souza, Alberto Krone-Martins, Emille E. O. Ishida, Benedetta Ciardi
We construct a theoretical model to predict the number of orphan afterglows
(OA) from gamma-ray bursts (GRBs) triggered by primordial metal free (Pop III)
stars expected to be observed by the Gaia mission. In particular, we consider
primordial metal free stars which were affected by radiation from other stars
(Pop III.2) as a possible target.
We use a semi-analytical approach, with the inclusion of all relevant
feedback effects, to construct the cosmic star formation history and its
connection with GRBs cumulative number. The OA events are generated via
Monte-Carlo method, and realistic simulations of Gaia's scanning law are
performed to derive the observation probability expectation. We show that $\sim
0.4\%$ of all Pop III.2 afterglows should appear in the sky above of Gaia
observational flux limit. Combining this result with simulations of Gaia's
scanning law, we expect to observe an average of $\sim 13\% \pm 7\%$ of all OA
above the observational sensitivity.
View original:
http://arxiv.org/abs/1112.6270
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