The origin of dust in high redshift QSOs: the case of SDSS J1148+5251

TL;DR

This paper develops a semi-analytical model to study the formation and evolution of high-redshift quasars, focusing on dust origin, black hole growth, and galaxy evolution, applied specifically to SDSS J1148+5251 at redshift 6.4.

Contribution

It introduces a comprehensive model that combines galaxy formation, black hole growth, and dust evolution processes in high-redshift QSOs, applied to a specific observed quasar.

Findings

Dust formation in SN ejecta and AGB stars is crucial for high-redshift QSOs.

Galactic winds driven by AGN feedback regulate black hole growth and star formation.

Different star formation histories significantly affect dust and galaxy evolution in the model.

Abstract

We present a semi-analytical model for the formation and evolution of a high redshift quasar (QSO). We reconstruct a set of hierarchical merger histories of a 10^13 Msun dark matter halo and model the evolution of the corresponding galaxy and of its central super massive black hole. The code GAMETE/QSODUST consistently follows: the black hole assembly via both coalescence with other black holes and gas accretion; the build up and star formation history of the quasar host galaxy, driven by binary mergers and mass accretion; the evolution of gas, stars, metals in the interstellar medium (ISM), accounting for mass exchanges with the external medium (infall and outflow processes); dust formation in Supernova (SN) ejecta and in the stellar atmosphere of Asymptotic Giant Branch (AGB) stars, dust destruction by interstellar shocks and grain growth in molecular clouds; the AGN feedback which powers a galactic-scale wind, self-regulating the black hole growth and eventually halting star formation.We use this model to study the case of SDSS J1148+5251 observed at redshift 6.4, exploring different star formation histories for the QSO host galaxy.