The study of the spectral energy distribution (SED) of active galactic nuclei (AGN) plays an important role in several aspects of the evolution of the galaxy. In this work, we model the black hole (BH) accretion flow for a wide range of BH mass and accretion rate. The accretion flow is divided into two regimes based on the Eddington-normalized accretion rate value - the ADAFs for low accretion rate objects and the modified magnetic reconnection-heated disk-corona model for high accretion rate objects. With BH properties generated by the semi-analytical model of galaxy formation L-Galaxies and Millennium-style dark matter simulation, we predicted AGN luminosity functions in different photometric bands that align well with observational data out to redshift z<1. Further, in the study of reionization, the role of AGNs in ionizing the intergalactic medium has been a subject of debate. Some recent observational studies and simulations suggest a negligible contribution of AGN, although many studies hold for the opposite as well. Because the ionizing photon output explicitly depends on the adopted AGN SED, we show that by replacing the commonly adopted shape-invariant power-law SED with our disk-corona SED, high redshift AGNs could produce more ionizing photons, hence could have played a more critical role than previously estimated.
BIO
Tong Su is a Master's student at the National Astronomical Observatories of China (NAOC), under the supervision of Professor Qi Guo. Her research interest lies in the field of cosmological simulation, particularly in the prescription of Active Galactic Nuclei (AGN) and how they would influence the evolution of galaxies and the simulated universe as a whole.
Host: Daniele Spinoso
