Sep. 17

Dust in the Early Universe

In the last few years mm and submm observations of high redshift quasars and galaxies have provided a powerful way of probing the very existence and properties of dust within 1 Gyr of the Big Bang. It is generally believed that at these cosmic times dust could have only condensed in the explosive ejecta of supernovae since intermediate-to-low mass stars did not have time to evolve off the main sequence into the dust-condensation stage. To account for the dust masses observed at z > 6, about 1 Msun of dust per supernova needs to be produced, in agreement with the condensation efficiencies predicted by supernova dust nucleation models. However, the largest dust masses measured so far in supernova ejecta are about two orders of magnitude smaller. Conversely, indications for supernova dust beyond z ~ 6 have recently come from observations of dust reddening of the host galaxies of a z = 6.2 quasars and z = 6.3 gamma-ray burst.

In this talk, we will review the recent advancements made in this controversial subject. We will present the results of recent models for dust production in supernova ejecta and intermediate mass stars and its subsequent evolution in the interstellar medium of high redshift galaxies. We will also discuss the implications of an early epoch of dust formation for the cosmic transition between Population III and Population II stars.

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Raffaella Schneider

INAF/Osservatorio Astronomico di Roma

host: Volker Bromm