2019/06/10 by David Garofalo, Garofalo, David, D. J. Christian +3
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · pdf · doi:10.48550/arxiv.1906.06995
openalex publication_date 2019/06/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
By exploring more than sixty thousand quasars from the Sloan Digital Sky\nSurvey Data Release 5, Steinhardt & Elvis discovered a sub-Eddington boundary\nand a redshift-dependent drop-off at higher black hole mass, possible clues to\nthe growth history of massive black holes. Our contribution to this special\nissue of Universe amounts to an application of a model for black hole accretion\nand jet formation to these observations. For illustrative purposes we include\nabout 100,000 data points from the Sloan Digital Sky Survey Data Release 7\nwhere the sub-Eddington boundary is also visible, and propose a theoretical\npicture that explains these features. By appealing to thin disk theory and both\nthe lower accretion efficiency and the time evolution of jetted quasars\ncompared to non-jetted quasars in our 'gap paradigm', we explain two features\nof the sub-Eddington boundary. First, we show that a drop-off on the quasar\nmass-luminosity plane for larger black hole mass occurs at all redshifts. But\nthe fraction of jetted quasars is directly related to the merger function in\nthis paradigm, which means the jetted quasar fraction drops with decrease in\nredshift, which allows us to explain a second feature of the sub-Eddington\nboundary, namely a redshift dependence of the slope of the quasar\nmass-luminosity boundary at high black hole mass stemming from a change in\nradiative efficiency with time. We are able to reproduce the mass dependence\nof, as well as the oscillating behavior in, the slope of the sub-Eddington\nboundary as a function of time. The basic physical idea involves retrograde\naccretion occurring only for a subset of the more massive black holes which\nimplies that most spinning black holes in our model are prograde accretors. In\nshort, this paper amounts to a qualitative overview of how a sub-Eddington\nboundary naturally emerges in the gap paradigm.\n