Name: Yuexing Li
Institution: Harvard-Smithsonian Center for Astrophysics

University of Washington

Astrolunch

Abstract:
The discovery of luminous quasars at z~6 challenges theoretical models to explain the early formation of supermassive black holes and massive galaxies when the Universe was less than 1 billion years old. I'll present the first multi-scale simulations that, together with a self-regulated model for the SMBH growth, produce a luminous quasar at z ~ 6.5 in the LCDM cosmology, which resembles the most distant quasar observed, SDSS J1148+5251. The IR calculations show that this quasar at z~6.5 has a SED that is similar to that of J1148, and that the system evolves from cold ULIRG to warm ULIRG as it transforms from starburst to quasar. Furthermore, the ionization from stars is found to be significant. Large HII region of up to 10 Mpc by stars were already in place before the peak quasar activity, suggesting that stars may play a more important role in reionization than quasars.