scholarly journals Massive and supermassive black holes in the contemporary and early Universe and problems in cosmology and astrophysics

2018 ◽  
Vol 61 (2) ◽  
pp. 115-132 ◽  
Author(s):  
A D Dolgov
2019 ◽  
Vol 60 (2) ◽  
pp. 111-126 ◽  
Author(s):  
Aaron Smith ◽  
Volker Bromm

Author(s):  
Tyrone E. Woods ◽  
Bhaskar Agarwal ◽  
Volker Bromm ◽  
Andrew Bunker ◽  
Ke-Jung Chen ◽  
...  

Abstract In recent years, the discovery of massive quasars at $z\sim7$ has provided a striking challenge to our understanding of the origin and growth of supermassive black holes in the early Universe. Mounting observational and theoretical evidence indicates the viability of massive seeds, formed by the collapse of supermassive stars, as a progenitor model for such early, massive accreting black holes. Although considerable progress has been made in our theoretical understanding, many questions remain regarding how (and how often) such objects may form, how they live and die, and how next generation observatories may yield new insight into the origin of these primordial titans. This review focusses on our present understanding of this remarkable formation scenario, based on the discussions held at the Monash Prato Centre from November 20 to 24, 2017, during the workshop ‘Titans of the Early Universe: The Origin of the First Supermassive Black Holes’.


2021 ◽  
Vol 4 (1) ◽  

Recent observations show that there are many more and much older black holes than previously known. What is particularly puzzling is that supermassive black holes containing more than a billion solar masses already existed in the very early universe. To date, there is no conclusive explanation for how such gravity monsters could have been created in such a short time after the Big Bang. The "Cosmic Time Hypothesis (CTH)" offers a solution to this problem [1]. According to this hypothesis, the early universe had much more time at its disposal than according to the "present-time scale" and the material-condensing forces were much stronger than now. Therefore, objects with extremely large masses could form in a very short "today-time".


Recent observations show that there are many more and much older black holes than previously known. What is particularly puzzling is that supermassive black holes containing more than a billion solar masses already existed in the very early universe. To date, there is no conclusive explanation for how such gravity monsters could have been created in such a short time after the Big Bang. The “Cosmic Time Hypothesis (CTH)” offers a solution to this problem [1]. According to this hypothesis, the early universe had much more time at its disposal than according to the “present-time scale” and the material-condensing forces were much stronger than now. Therefore, objects with extremely large masses could form in a very short “todaytime”.


2020 ◽  
Vol 496 (2) ◽  
pp. 1115-1123
Author(s):  
K Boshkayev ◽  
A Idrissov ◽  
O Luongo ◽  
D Malafarina

ABSTRACT We consider the observational properties of a static black hole space–time immersed in a dark matter envelope. We investigate how the modifications to geometry induced by the presence of dark matter affect the luminosity of the black hole’s accretion disc. We show that the same disc luminosity as produced by a black hole in vacuum may be produced by a smaller black hole surrounded by dark matter under certain conditions. In particular, we demonstrate that the luminosity of the disc is markedly altered by the presence of dark matter, suggesting that the mass estimation of distant supermassive black holes may be changed if they are immersed in dark matter. We argue that a similar effect holds in more realistic scenarios, and we discuss the refractive index related to dark matter lensing. Finally, we show how the results presented here may help to explain the observed luminosity of supermassive black holes in the early Universe.


Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 23
Author(s):  
Tullia Sbarrato

Blazars are active galactic nuclei characterized by relativistic jets launched in the vicinity of the central engine (i.e., a supermassive black hole), which are oriented close to our line of sight. Their peculiar orientation makes them very efficient tracers of the overall jetted population, and due to their brightness they can be visible up to very high redshifts. A deep knowledge of these objects can provide fundamental clues to the models of formation and growth of the first supermassive black holes, but the search for them in the early Universe must be careful and follow a systematic approach. The discovery in the last ∼15 years of extremely massive blazars at very high redshifts (MBH>109M⊙, z>4) revolutionized our perception of their earliest evolution: there seem to be different formation epochs for extremely massive black holes hosted in jetted (z∼4) and non-jetted (z∼2.5) systems. This is not easy to explain, since one would expect jetted sources to accrete less efficiently. Small differences in the population are also derived from the search for such high-z sources. We will go through the open questions in order to understand where the common knowledge stands and which steps must be taken to better understand the formation and common evolution of supermassive black holes and jets in the early Universe.


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