BH birth. today. active. dormant. active. active. dormant. a single episodic phase. Mass distribution Total: triple power law. Mass function in each redshift z -bin. Cosmological Evolution of the Duty Cycle of Quasars Jian-Min Wang, Yan-Mei Chen & Fan Zhang
a single episodic phase
Total: triple power law
in each redshift z-bin
Cosmological Evolution of the Duty Cycle of Quasars
Jian-Min Wang, Yan-Mei Chen & Fan Zhang
Institute of High Energy Physics, CAS, China, [email protected]
Abstract: The problem of the duty cycle related to the episodic activity of the black holes remains one of the major questions of the cosmological evolution of quasars. In this work, we obtain quasar mass function based on analyses of a large sample of quasars from SDSS with z ≤ 2.1. We then get the duty cycle based on Sołtan’s argument, using quasar mass function and luminosity function. We find that the duty cycle has a strong evolution which follows the history of the cosmic star formation rate (SFR) density in the universe.