January 30

Yuexing Li (Penn State)

Galaxies and Quasars at the Cosmic Dawn

Recent multi-wavelength surveys have discovered hundreds of star-forming galaxies and dozens of luminous quasars at redshift z > 6. They indicate the presence of large stellar population of ~10¹¹ M_¤ and supermassive black holes of ~10⁹ M_¤ when the Universe was only a few hundred million years after the Big Bang. These frontier observations challenge theoretical models to explain, and require a combination of structure formation with radiative transfer to understand the underlying physical processes. I will present state-of-the-art calculations, which combine multi-scale cosmological simulations with multi-wavelength radiative transfer, to follow the formation, evolution, and multi-band properties of galaxies and quasars in the early Universe. Our models demonstrate that the exciting observations of the most distant objects are consistent with predictions from the standard LCDM cosmology. The earliest galaxies and quasars form in massive halos hierarchically and are highly clustered, which may provide patchy ionization of the surrounding medium. In addition, I will discuss the need for such a modeling in future study of galaxy formation in all epochs, and in the search for the first galaxies and quasars with upcoming observatories such as ALMA and JWST.