Recent Progress in Relativistic Astrophysics

A special issue of Universe (ISSN 2218-1997).

Deadline for manuscript submissions: closed (31 August 2019) | Viewed by 3837

Special Issue Editors


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Guest Editor
1. Center for Field Theory and Particle Physics and Department of Physics, Fudan University, Shanghai, China
2. Theoretical Astrophysics, Eberhard Karls Universität Tübingen, Tübingen, Germany
Interests: tests of general relativity and of alternative theories of gravity; black holes; quantum gravity phenomenology; high-energy astrophysics; physics of the early Universe
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Guest Editor
Theoretical Astrophysics, Eberhard Karls Universität Tübingen, Tübingen, Germany
Interests: black hole astrophysics; gravitational waves; gravitational collapse; general relativity; tests of alternative theories of gravity

Special Issue Information

Dear Colleagues,

It is a pleasure to announce the Special Issue "Recent Progress in Relativistic Astrophysics". Black holes and neutron stars are the most extreme objects that can be found in the Universe and an ideal laboratory for testing fundamental physics. Thanks to new observations facilities, in the past 20 years there has been tremendous progress in the understanding of these objects and of their astrophysical environment. Recent detections of gravitational waves have opened a new and complementary window to the study of compact objects. While some questions have been addressed, others are still open, and new questions have arisen. The aim of this Special Issue is to review recent progress in the field of relativistic astrophysics and to point out future directions. All submissions will be peer reviewed before being accepted for publication.

Prof. Dr. Cosimo Bambi
Dr. Sourabh Nampalliwar
Guest Editors

Manuscript Submission Information

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Keywords

  • high energy astrophysics
  • black holes
  • neutron stars
  • gravitational waves

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Published Papers (1 paper)

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Research

19 pages, 4131 KiB  
Article
The Sub-Eddington Boundary for the Quasar Mass–Luminosity Plane: A Theoretical Perspective
by David Garofalo, Damian J. Christian and Andrew M. Jones
Universe 2019, 5(6), 145; https://doi.org/10.3390/universe5060145 - 11 Jun 2019
Cited by 13 | Viewed by 3343
Abstract
By exploring more than sixty thousand quasars from the Sloan Digital Sky Survey Data Release 5, Steinhardt & Elvis discovered a sub-Eddington boundary and a redshift-dependent drop-off at higher black hole mass, possible clues to the growth history of massive black holes. Our [...] Read more.
By exploring more than sixty thousand quasars from the Sloan Digital Sky Survey Data Release 5, Steinhardt & Elvis discovered a sub-Eddington boundary and a redshift-dependent drop-off at higher black hole mass, possible clues to the growth history of massive black holes. Our contribution to this special issue of Universe amounts to an application of a model for black hole accretion and jet formation to these observations. For illustrative purposes, we include ~100,000 data points from the Sloan Digital Sky Survey Data Release 7 where the sub-Eddington boundary is also visible and propose a theoretical picture that explains these features. By appealing to thin disk theory and both the lower accretion efficiency and the time evolution of jetted quasars compared to non-jetted quasars in our “gap paradigm”, we explain two features of the sub-Eddington boundary. First, we show that a drop-off on the quasar mass-luminosity plane for larger black hole mass occurs at all redshifts. But the fraction of jetted quasars is directly related to the merger function in this paradigm, which means the jetted quasar fraction drops with decrease in redshift, which allows us to explain a second feature of the sub-Eddington boundary, namely a redshift dependence of the slope of the quasar mass–luminosity boundary at high black hole mass stemming from a change in radiative efficiency with time. We are able to reproduce the mass dependence of, as well as the oscillating behavior in, the slope of the sub-Eddington boundary as a function of time. The basic physical idea involves retrograde accretion occurring only for a subset of the more massive black holes, which implies that most spinning black holes in our model are prograde accretors. In short, this paper amounts to a qualitative overview of how a sub-Eddington boundary naturally emerges in the gap paradigm. Full article
(This article belongs to the Special Issue Recent Progress in Relativistic Astrophysics)
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