FM10.6.01 — Galactic chemical evolution and GRB host identification

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Aug 13th at 8:30 AM until 8:42 AM

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Author(s): Francesca Matteucci1, Valentina Grieco1

Institution(s): 1. Trieste University

The nature of some GRB host galaxies will be investigated by means of chemical evolution models of galaxies of different morphological type (ellipticals, spirals and irregulars).
The adopted models follow the evolution of the abundances of H, He, C, N, O, alpha-elements, Fe, Ni and Zn. and include also the evolution of dust. By comparing theoretical predictions with the observed abundance patterns in hosts of GRBs we are able to determine which kind of galaxy they are. We analyze three GRB ( GRB 081008; GRB 120327A; GRB 120815) host galaxies and conclude that one (GRB 120815) should be a proto-spheroid catched in the phase of active star formation, while for the other two the situation is more uncertain although we suggest that one is also probably a spheroid and the other a spiral galaxy.
We estimate the chemical ages of the host galaxies to be in the range 15-320 Myr. Finally, we compute the evolution with redshift of the cosmic dust production as a function of redshift in an unitary volume of the universe, under different assumptions about the number density evolution of galaxies.