Accretions of Tsallis, Rényi and Sharma–Mittal dark energies onto higher-dimensional Schwarzschild black hole and Morris–Thorne wormhole

2021 ◽  
pp. 2150081
Author(s):  
Tanwi Bandyopadhyay ◽  
Ujjal Debnath
Keyword(s):  
Black Hole ◽  
Dark Energy ◽  
Cold Dark Matter ◽  
Rate Of Change ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
New Agegraphic Dark Energy ◽  
Dark Energy Component ◽  
Higher Dimensional ◽  
Almost All

In this work, we study the dark energy accretion phenomena onto [Formula: see text]-dimensional Schwarzschild black hole and [Formula: see text]-dimensional Morris–Thorne wormhole. We obtain the [Formula: see text]-dimensional Schwarzschild black hole mass and [Formula: see text]-dimensional Morris–Thorne wormhole mass and their rate of change of masses due to accretion. For the dark energy component, we consider Tsallis, modified Rényi and “modified” Sharma–Mittal holographic dark energy (HDE) and new agegraphic dark energy (NADE). We also find the black hole mass and the wormhole mass in terms of redshift when cold dark matter and the specified forms of dark energies accrete onto them. In most cases, the black hole mass increases, and wormhole mass decreases for HDE and NADE accretions. The only exception is the Sharma–Mittal NADE, where the black hole mass decreases and wormhole mass increases during the evolution of the Universe. However, the slope of increasing/decreasing mass significantly depends on the dimension in almost all cases.

scholarly journals C iv black hole mass measurements with the Australian Dark Energy Survey (OzDES)

2019 ◽  
Vol 487 (3) ◽  
pp. 3650-3663 ◽  
Author(s):  
J K Hoormann ◽  
P Martini ◽  
T M Davis ◽  
A King ◽  
C Lidman ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Energy ◽  
Emission Line ◽  
Galaxy Evolution ◽  
Supermassive Black Holes ◽  
Black Hole Mass ◽  
Mass Measurements ◽  
Dark Energy Survey ◽  
Energy Survey

ABSTRACT Black hole mass measurements outside the local Universe are critically important to derive the growth of supermassive black holes over cosmic time, and to study the interplay between black hole growth and galaxy evolution. In this paper, we present two measurements of supermassive black hole masses from reverberation mapping (RM) of the broad C iv emission line. These measurements are based on multiyear photometry and spectroscopy from the Dark Energy Survey Supernova Program (DES-SN) and the Australian Dark Energy Survey (OzDES), which together constitute the OzDES RM Program. The observed reverberation lag between the DES continuum photometry and the OzDES emission line fluxes is measured to be $358^{+126}_{-123}$ and $343^{+58}_{-84}$ d for two quasars at redshifts of 1.905 and 2.593, respectively. The corresponding masses of the two supermassive black holes are 4.4 × 109 and 3.3 × 109 M⊙, which are among the highest redshift and highest mass black holes measured to date with RM studies. We use these new measurements to better determine the C iv radius−luminosity relationship for high-luminosity quasars, which is fundamental to many quasar black hole mass estimates and demographic studies.

Analysis of entropy corrected holographic and new agegraphic dark energy models in generalized Rastall gravity

2020 ◽  
Vol 35 (28) ◽  
pp. 2050175
Author(s):  
Sayani Maity ◽  
Mahasweta Biswas ◽  
Ujjal Debnath
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Graphical Analysis ◽  
Future Singularity ◽  
Agegraphic Dark Energy ◽  
New Agegraphic Dark Energy ◽  
Energy Models ◽  
Dark Energy Component ◽  
The Stability

This work deals with two fluid system in the framework of generalized Rastall gravity theory. One component represents dark energy whereas the other is dark matter. For the dark energy component, entropy corrected holographic and entropy corrected new agegraphic dark energy models in power-law and logarithmic versions are taken into account. For this study, we assume two classes of scale factors in which one corresponds to the future singularity and another corresponds to the initial singularity. For each of the entropy corrected dark energy models, the cosmological parameters such as Hubble parameter, deceleration parameter and equation of state parameter are calculated and their implications are established. Furthermore, to describe the stability analysis of the models, the behaviors of the squared speed of sound are analyzed graphically for each of these models. From the graphical analysis of [Formula: see text] plane, the thawing or freezing regions of all the models are determined.

DE SITTER-SCHWARZSCHILD BLACK HOLE: ITS PARTICLELIKE CORE AND THERMODYNAMICAL PROPERTIES

1996 ◽  
Vol 05 (05) ◽  
pp. 529-540 ◽  
Author(s):  
I.G. DYMNIKOVA
Keyword(s):  
Black Hole ◽  
Lower Limit ◽  
Mass Parameter ◽  
Hawking Temperature ◽  
Einstein Equations ◽  
Black Hole Mass ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Schwarzschild Solution ◽  
Second Order Phase Transition

We analyze the globally regular solution of the Einstein equations describing a black hole whose singularity is replaced by the de Sitter core. The de Sitter—Schwarzschild black hole (SSBH) has two horizons. Inside of it there exists a particlelike structure hidden under the external horizon. The critical value of mass parameter M cr1 exists corresponding to the degenerate horizon. It represents the lower limit for a black-hole mass. Below M cr1 there is no black hole, and the de Sitter-Schwarzschild solution describes a recovered particlelike structure. We calculate the Hawking temperature of SSBH and show that specific heat is broken and changes its sign at the value of mass M cr 2>M cr 1 which means that a second-order phase transition occurs at that point. We show that the Hawking temperature drops to zero when a mass approaches the lower limit M cr1 .

scholarly journals Matter accretion onto a conformal gravity black hole

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
G. Abbas ◽  
A. Ditta
Keyword(s):  
Black Hole ◽  
Equations Of State ◽  
Accretion Rate ◽  
Black Hole Mass ◽  
Conformal Gravity ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Mass Rate ◽  
Mass Accretion Rate ◽  
The Impact

AbstractThe accretion of test fluids flowing onto a black hole is investigated. Particularly, by adopting a dynamical Hamiltonian approach, we are capable to find the critical points for various cases of black hole in conformal gravity. In these cases, we have analyzed the general solutions of accretion employing the isothermal equations of state. The steady state and spherically symmetric accretion of different test fluids onto the conformal gravity black hole has been considered. Further, we have classified these flows in the context of equations of state and the cases of conformal gravity black hole. The new behavior of polytropic fluid accretion is also discussed in all three cases of black hole. Black hole mass accretion rate is the most important part of this research in which we have investigated that the Schwarzschild black hole produce a typical signature than the conformal gravity black hole and Schwarzschild–de Sitter black hole. The critical fluid flow and the mass accretion rate have been presented graphically by the impact parameters $$\beta $$ β , $$\gamma $$ γ , k and these parameters have great significance. Additionally, the maximum mass rate of accretion fall near the universal and Killing horizons and minimum rate of accretion occurs in between these regions. Finally, the results are compared with the different cases of black hole available in the literature.

scholarly journals Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

2020 ◽  
Author(s):  
Grigory Volovik
Keyword(s):  
Black Hole ◽  
Quantum Tunneling ◽  
Black Hole Thermodynamics ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Dimensionless Quantity ◽  
White Hole ◽  
Thermodynamic Variable ◽  
Euclidean Action ◽  
Thermodynamics Of Black Holes

The thermodynamics of black holes is discussed for the case, when the Newton constant G is not a constant, but is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: d S BH = − A d K + d M T BH , where the gravitational coupling K = 1 / 4 G , M is the black hole mass, A is the area of horizon, and T BH is Hawking temperature. From this first law it follows that the dimensionless quantity M 2 / K is the adiabatic invariant, which in principle can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that K and A serve as dynamically conjugate variables. This allows us to calculate the quantum tunneling from the black hole to the white hole, and determine the temperature and entropy of the white hole.

scholarly journals Effective GUP-modified Raychaudhuri equation and black hole singularity: four models

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Keagan Blanchette ◽  
Saurya Das ◽  
Saeed Rastgoo
Keyword(s):  
Black Hole ◽  
Proper Time ◽  
Generalized Uncertainty Principle ◽  
Rate Of Change ◽  
Conjugate Points ◽  
Raychaudhuri Equation ◽  
Schwarzschild Black Hole ◽  
Effective Dynamics ◽  
Singularity Theorems ◽  
Black Hole Singularity

Abstract The classical Raychaudhuri equation predicts the formation of conjugate points for a congruence of geodesics, in a finite proper time. This in conjunction with the Hawking-Penrose singularity theorems predicts the incompleteness of geodesics and thereby the singular nature of practically all spacetimes. We compute the generic corrections to the Raychaudhuri equation in the interior of a Schwarzschild black hole, arising from modifications to the algebra inspired by the generalized uncertainty principle (GUP) theories. Then we study four specific models of GUP, compute their effective dynamics as well as their expansion and its rate of change using the Raychaudhuri equation. We show that the modification from GUP in two of these models, where such modifications are dependent of the configuration variables, lead to finite Kretchmann scalar, expansion and its rate, hence implying the resolution of the singularity. However, the other two models for which the modifications depend on the momenta still retain their singularities even in the effective regime.

scholarly journals Quasar evolution: black hole mass and accretion rate determination

2006 ◽  
Vol 2 (S238) ◽  
pp. 83-86
Author(s):  
Deborah Dultzin-Hacyan ◽  
Paola Marziani ◽  
C. Alenka Negrete ◽  
Jack W. Sulentic
Keyword(s):  
Black Hole ◽  
Accretion Rate ◽  
Selection Effects ◽  
Black Hole Mass ◽  
Spectral Evolution ◽  
Spatially Resolved ◽  
Central Engine ◽  
Line Region ◽  
Ratio Determination ◽  
Almost All

AbstractAccurate measurements of emission line properties are crucial to understand the physics of the broad line region in quasars. This region consists of warm gas that is closest to the quasar central engine and has not been spatially resolved for almost all sources. We present here an analysis of optical and IR data for a large sample of quasars, covering the Hi Hβ spectral region in the redshift range 0 ≲ z ≲ 2.5. Spectra were interpreted within the framework of the the so-called “eigenvector 1” parameter space, which can be viewed as a tentative H-R diagram for quasars. We stress the lack of spectral evolution in the low ionization lines of quasars, with prominent Fe ii emission also at z ≳ 2. We also show how selection effects influence the ability to find quasars radiating at low Eddington ratio in flux-limited surveys. The quasar similarity at different redshift is probably due to the absence of super-Eddington radiators (at least within the caveats of black hole mass and Eddington ratio determination discussed in this paper) as well as to the limited Eddington ratio range within which quasars seem to radiate.

scholarly journals Proposal for the proper gravitational energy–momentum tensor

2016 ◽  
Vol 31 (26) ◽  
pp. 1650151 ◽  
Author(s):  
Katsutaro Shimizu
Keyword(s):  
Black Hole ◽  
Energy Momentum Tensor ◽  
Momentum Conservation ◽  
Momentum Tensor ◽  
Gravitational Energy ◽  
Coordinate Transformations ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Flrw Universe ◽  
Energy Momentum Conservation

We propose a gravitational energy–momentum (GEMT) tensor of the general relativity obtained using Noether’s theorem. It transforms as a tensor under general coordinate transformations. One of the two indices of the GEMT labels a local Lorentz frame that satisfies the energy–momentum conservation law. The energies for a gravitational wave, a Schwarzschild black hole and a Friedmann–Lemaitre–Robertson–Walker (FLRW) universe are calculated as examples. The gravitational energy of the Schwarzschild black hole exists only outside the horizon, its value being the negative of the black hole mass.

scholarly journals Cosmological isotropic matter–energy generalizations of Schwarzschild and Kerr metrics

2016 ◽  
Vol 25 (10) ◽  
pp. 1650088
Author(s):  
Metin Arik ◽  
Yorgo Senikoglu
Keyword(s):  
Black Hole ◽  
Dark Energy ◽  
Black Hole Solution ◽  
State Parameter ◽  
Time Dependent ◽  
Schwarzschild Black Hole ◽  
Field Equations ◽  
Rotating Black Hole ◽  
Special Solutions ◽  
Matter Energy

We present a time-dependent isotropic fluid solution around a Schwarzschild black hole. We offer the solutions and discuss the effects on the field equations and the horizon. We derive the energy density, pressure and the equation of state parameter. In the second part, we generalize the rotating black hole solution to an expanding universe. We derive from the proposed metric the special solutions of the field equations for the dust approximation and the dark energy solution. We show that the presence of a rotating black hole does not modify the scale factor [Formula: see text] law for dust, nor [Formula: see text] and [Formula: see text] for dark energy.

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