scholarly journals Testing general relativity and probing the merger history of massive black holes with LISA

2005 ◽  
Vol 22 (18) ◽  
pp. S943-S954 ◽  
Author(s):  
Emanuele Berti ◽  
Alessandra Buonanno ◽  
Clifford M Will
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Massive Black Holes ◽  
History Of

scholarly journals The Merging History of Massive Black Holes

2004 ◽  
pp. 227-230 ◽  
Author(s):  
Marta Volonteri ◽  
Francesco Haardt ◽  
Piero Madau ◽  
Alberto Sesana
Keyword(s):  
Black Holes ◽  
Massive Black Holes ◽  
History Of

scholarly journals The Clustering Dynamics of Primordial Black Boles in N-Body Simulations

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 18
Author(s):  
Manuel Trashorras ◽  
Juan García-Bellido ◽  
Savvas Nesseris
Keyword(s):  
Black Holes ◽  
Binary Systems ◽  
Orbital Parameter ◽  
Galactic Halos ◽  
Massive Black Holes ◽  
Close Encounters ◽  
Mass Ratios ◽  
History Of ◽  
Mass Segregation ◽  
Rate Of Evaporation

We explore the possibility that Dark Matter (DM) may be explained by a nonuniform background of approximately stellar mass clusters of Primordial Black Holes (PBHs) by simulating the evolution from recombination to the present with over 5000 realisations using a Newtonian N-body code. We compute the cluster rate of evaporation and extract the binary and merged sub-populations along with their parent and merger tree histories, lifetimes and formation rates, the dynamical and orbital parameter profiles, the degree of mass segregation and dynamical friction and power spectrum of close encounters. Overall, we find that PBHs can constitute a viable DM candidate, and that their clustering presents a rich phenomenology throughout the history of the Universe. We show that binary systems constitute about 9.5% of all PBHs at present, with mass ratios of q¯B=0.154, and total masses of m¯T,B=303M⊙. Merged PBHs are rare, about 0.0023% of all PBHs at present, with mass ratios of q¯B=0.965 with total and chirp masses of m¯T,B=1670M⊙ and m¯c,M=642M⊙, respectively. We find that cluster puffing up and evaporation leads to bubbles of these PBHs of order 1 kpc containing at present times about 36% of objects and mass, with one-hundred pc-sized cores. We also find that these PBH sub-haloes are distributed in wider PBH haloes of order hundreds of kpc, containing about 63% of objects and mass, coinciding with the sizes of galactic halos. We find at last high rates of close encounters of massive Black Holes (M∼1000M⊙), with ΓS=(1.2+5.9−0.9)×107yr−1Gpc−3 and mergers with ΓM=1337±41yr−1Gpc−3.

scholarly journals Can fermionic dark matter mimic supermassive black holes?

2019 ◽  
Vol 28 (14) ◽  
pp. 1943003 ◽  
Author(s):  
C. R. Argüelles ◽  
A. Krut ◽  
J. A. Rueda ◽  
R. Ruffini
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Dark Matter ◽  
Rotation Curve ◽  
Compact Object ◽  
Mass Range ◽  
Unified Approach ◽  
Massive Black Holes ◽  
Degeneracy Pressure ◽  
Relaxed System

We analyze the intriguing possibility of explaining both dark mass components in a galaxy: the dark matter (DM) halo and the supermassive dark compact object lying at the center, by a unified approach in terms of a quasi-relaxed system of massive, neutral fermions in general relativity. The solutions to the mass distribution of such a model that fulfill realistic halo boundary conditions inferred from observations, develop a high-density core supported by the fermion degeneracy pressure able to mimic massive black holes at the center of galaxies. Remarkably, these dense core-diluted halo configurations can explain the dynamics of the closest stars around Milky Way’s center (SgrA*) all the way to the halo rotation curve, without spoiling the baryonic bulge-disk components, for a narrow particle mass range [Formula: see text]–[Formula: see text][Formula: see text]keV.

scholarly journals The Assembly of the First Massive Black Holes

2020 ◽  
Vol 58 (1) ◽  
pp. 27-97 ◽  
Author(s):  
Kohei Inayoshi ◽  
Eli Visbal ◽  
Zoltán Haiman
Keyword(s):  
Black Holes ◽  
First Generation ◽  
Stellar Mass ◽  
Host Galaxy ◽  
Initial Growth ◽  
Host Galaxies ◽  
Potential Wells ◽  
Massive Black Holes ◽  
History Of ◽  
Gas Accretion

The existence of ∼109M⊙ supermassive black holes (SMBHs) within the first billion years of the Universe has stimulated numerous ideas for the prompt formation and rapid growth of black holes (BHs) in the early Universe. Here, we review ways in which the seeds of massive BHs may have first assembled, how they may have subsequently grown as massive as ∼109M⊙, and how multimessenger observations could distinguish between different SMBH assembly scenarios. We conclude the following: ▪  The ultrarare ∼109 M⊙ SMBHs represent only the tip of the iceberg. Early BHs likely fill a continuum from the stellar-mass (∼10M⊙) to the supermassive (∼109) regimes, reflecting a range of initial masses and growth histories. ▪  Stellar-mass BHs were likely left behind by the first generation of stars at redshifts as high as ∼30, but their initial growth typically was stunted due to the shallow potential wells of their host galaxies. ▪  Conditions in some larger, metal-poor galaxies soon became conducive to the rapid formation and growth of massive seed holes, via gas accretion and by mergers in dense stellar clusters. ▪  BH masses depend on the environment (such as the number and properties of nearby radiation sources and the local baryonic streaming velocity) and on the metal enrichment and assembly history of the host galaxy. ▪  Distinguishing between assembly mechanisms will be difficult, but a combination of observations by the Laser Interferometer Space Antenna (probing massive BH growth via mergers) and by deep multiwavelength electromagnetic observations (probing growth via gas accretion) is particularly promising.

scholarly journals Stephen William Hawking CH CBE. 8 January 1942—14 March 2018

2019 ◽  
Vol 66 ◽  
pp. 267-308
Author(s):  
Bernard J. Carr ◽  
George F. R. Ellis ◽  
Gary W. Gibbons ◽  
James B. Hartle ◽  
Thomas Hertog ◽  
...  
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Quantum Mechanics ◽  
Large Scale ◽  
Early Years ◽  
Singularity Theorems ◽  
Post Graduate Student ◽  
History Of ◽  
The 1960S ◽  
The Universe

Stephen Hawking's contributions to the understanding of gravity, black holes and cosmology were truly immense. They began with the singularity theorems in the 1960s followed by his discovery that black holes have an entropy and consequently a finite temperature. Black holes were predicted to emit thermal radiation, what is now called Hawking radiation. He pioneered the study of primordial black holes and their potential role in cosmology. His organization of and contributions to the Nuffield Workshop in 1982 consolidated the picture that the large-scale structure of the universe originated as quantum fluctuations during the inflationary era. Work on the interplay between quantum mechanics and general relativity resulted in his formulation of the concept of the wavefunction of the universe. The tension between quantum mechanics and general relativity led to his struggles with the information paradox concerning deep connections between these fundamental areas of physics. These achievements were all accomplished following the diagnosis during the early years of Stephen's studies as a post-graduate student in Cambridge that he had incurable motor neuron disease—he was given two years to live. Against all the odds, he lived a further 55 years. The distinction of his work led to many honours and he became a major public figure, promoting with passion the needs of disabled people. His popular best-selling book, A brief history of time , made cosmology and his own work known to the general public world-wide. He became an icon for science and an inspiration to all.

Dark Bodies and Black Holes, Magic Circles and Montgolfiers: Light and Gravitation from Newton to Einstein

1993 ◽  
Vol 6 (1) ◽  
pp. 83-106
Author(s):  
Jean Eisenstaedt
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Field ◽  
Important Place ◽  
Propagation Of Light ◽  
History Of ◽  
Theory Of Gravitation ◽  
The 1960S ◽  
Bending Of Light

The ArgumentThe question of the possible existence of black holes is closely related to the question of the action of gravitation on the propagation of light. It has been raised recurrently from the when that Newton referred to a possible bending of light in his Opticks. And it relies on apparently simple questions: Is light subject to gravitation? What is the effect of a gravitational field on the propagation of light? Could a particle of light emitted by a star be retained by its gravitational field?From the end of the 1960s, the black hole idea has had a very important place in the relativistic literature, not to speak of the popularization of the theory. It turned out to be not only an important concept but also a tool that permitted us to understand general relativity better, indeed a tool that contributed greatly to changing the interpretation of Einstein's theory of gravitation. Here too I want to use this concept of the black hole to assist our understanding of the history of general relativity: the black hole is a fundamental milestone in the evolution of general relativity.

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