scholarly journals Uniqueness of extremal isolated horizons and their identification with horizons of all type D black holes

2021 ◽  
Author(s):  
David Matejov ◽  
Jiri Podolsky
Keyword(s):  
Black Holes ◽  
Type D ◽  
Isolated Horizons

scholarly journals Scalar hairy black holes and scalarons in the isolated horizons formalism

2006 ◽  
Vol 73 (8) ◽  
Author(s):  
Alejandro Corichi ◽  
Ulises Nucamendi ◽  
Marcelo Salgado
Keyword(s):  
Black Holes ◽  
Isolated Horizons ◽  
Hairy Black Holes

scholarly journals CHARGED BLACK HOLES IN VAIDYA BACKGROUNDS: HAWKING'S RADIATION

2010 ◽  
Vol 19 (04) ◽  
pp. 437-464 ◽  
Author(s):  
NG IBOHAL ◽  
L. KAPIL
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Einstein’S Field Equations ◽  
Field Equations ◽  
Naked Singularities ◽  
Charged Black Holes ◽  
Type D ◽  
Einstein's Field Equations ◽  
Vaidya Solution ◽  
The Individual

In this paper we propose a class of embedded solutions of Einstein's field equations describing nonrotating Reissner–Nordstrom–Vaidya and rotating Kerr–Newman–Vaidya black holes. The Reissner–Nordstrom–Vaidya is obtained by embedding Reissner–Nordstrom solution into the nonrotating Vaidya. Similarly, we also find the Kerr–Newman–Vaidya black hole, when Kerr–Newman embeds into the rotating Vaidya solution. The Reissner–Nordstrom–Vaidya solution is type D whereas the Kerr–Newman–Vaidya metric is algebraically special of type II by the Petrov classification of space–time. These embedded solutions can be expressed in the Kerr–Schild ansatze on different backgrounds. The energy–momentum tensors for both nonrotating as well as rotating embedded solutions satisfy the energy conservation equations which show that they are solutions of Einstein's field equations. The surface gravity, area, temperature and entropy are also presented for each embedded black hole. It is observed that the area of the embedded black holes is greater than the sum of the areas of the individual ones. By considering the charge to be a function of radial coordinates it is shown that there is a change in the masses of the variably charged black holes. If such radiation continues, the mass of the black hole will evaporate completely thereby forming "instantaneous" charged black holes and creating embedded negative mass naked singularities describing the possible the life of radiation embedded black holes during their continuous radiation processes.

scholarly journals Photon regions and shadows of accelerated black holes

2015 ◽  
Vol 24 (09) ◽  
pp. 1542024 ◽  
Author(s):  
Arne Grenzebach ◽  
Volker Perlick ◽  
Claus Lämmerzahl
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Boundary Curve ◽  
Kerr Metric ◽  
Axially Symmetric ◽  
De Sitter ◽  
Acceleration Parameter ◽  
Type D ◽  
Analytical Formulas ◽  
Photon Regions

In an earlier paper, we have analytically determined the photon regions and the shadows of black holes of the Plebański class of metrics which are also known as the Kerr–Newman–NUT–(anti-)de Sitter metrics. These metrics are characterized by six parameters: Mass, spin, electric and magnetic charges, gravitomagnetic NUT charge and the cosmological constant. Here, we extend this analysis to the Plebański–Demiański class of metrics which contains, in addition to these six parameters, the so-called acceleration parameter. All these metrics are axially symmetric and stationary type D solutions to the Einstein–Maxwell equations with a cosmological constant. We derive analytical formulas for the photon regions (i.e. for the regions that contain spherical lightlike geodesics) and for the boundary curve of the shadow as it is seen by an observer at Boyer–Lindquist coordinates (rO, ϑO) in the domain of outer communication. Whereas all relevant formulas are derived for the whole Plebański–Demiański class, we concentrate on the accelerated Kerr metric (i.e. only mass, spin and acceleration parameter are different from zero) when discussing the influence of the acceleration parameter on the photon region and on the shadow in terms of pictures. The accelerated Kerr metric is also known as the rotating C-metric. We discuss how our analytical formulas can be used for calculating the horizontal and vertical angular diameters of the shadow and we estimate these values for the black holes at the center of our Galaxy and at the center of M87.

scholarly journals The Petrov type D equation on genus >0 sections of isolated horizons

2018 ◽  
Vol 783 ◽  
pp. 415-420 ◽  
Author(s):  
Denis Dobkowski-Ryłko ◽  
Wojciech Kamiński ◽  
Jerzy Lewandowski ◽  
Adam Szereszewski
Keyword(s):  
Petrov Type ◽  
Type D ◽  
Isolated Horizons ◽  
Petrov Type D

scholarly journals New improved form of black holes of type D

2021 ◽  
Vol 104 (8) ◽  
Author(s):  
Jiří Podolský ◽  
Adam Vrátný
Keyword(s):  
Black Holes ◽  
Type D

The Type D Construct

2014 ◽  
Vol 30 (4) ◽  
pp. 283-288 ◽  
Author(s):  
Gesine Grande ◽  
Matthias Romppel ◽  
Matthias Michal ◽  
Elmar Brähler
Keyword(s):  
Social Functioning ◽  
Negative Affectivity ◽  
Population Based ◽  
Type D Personality ◽  
Social Orientation ◽  
German Population ◽  
Social Competencies ◽  
Social And Emotional ◽  
Type D ◽  
Worse Prognosis

The interaction of negative affectivity (NA) and social inhibition (SI), known as the Type D personality, is associated with a worse prognosis in cardiac patients. Until now, causal models have been speculative, and this is partly due to a lack of clarity related to the validity of SI, its role in emotion regulation, and the postulated independence of social and emotional functioning. To examine the construct validity of the Type D personality, we analyzed associations of NA and SI with different measures of affectivity, social anxiety, and social competencies in a German population-based representative sample (n = 2,495). Both NA and SI were associated with all other measures of social functioning and negative affect (all rs > .30) and showed considerable cross-loadings (NA: a 1 = .39, a 2 = .63; SI: a1 = .73 and a2 = .34) in a two-factor solution with the factors labeled as Social Functioning and Negative Affectivity. The SI subscale did not properly differentiate between social fears and social competencies, which emerged as rather different aspects of social functioning. Further studies should examine the effect of broader dimensions of social orientation and competencies and their interaction with NA on cardiac prognosis.

Illness Perception and Its Changes During Six Months After Cardiac Rehabilitation

2019 ◽  
Vol 26 (3) ◽  
pp. 90-100
Author(s):  
Justė Lukoševičiūtė ◽  
Kastytis Šmigelskas
Keyword(s):  
New York ◽  
Social Factors ◽  
Nyha Class ◽  
Illness Perception ◽  
Heart Association ◽  
Class Iii ◽  
Cognitive Representations ◽  
Coronary Syndrome ◽  
Type D ◽  
New York Heart Association

Abstract. Illness perception is a concept that reflects patients' emotional and cognitive representations of disease. This study assessed the illness perception change during 6 months in 195 patients (33% women and 67% men) with acute coronary syndrome, taking into account the biological, psychological, and social factors. At baseline, more threatening illness perception was observed in women, persons aged 65 years or more, with poorer functional capacity (New York Heart Association [NYHA] class III or IV) and comorbidities ( p < .05). Type D personality was the only independent factor related to more threatening illness perception (βs = 0.207, p = .006). At follow-up it was found that only self-reported cardiovascular impairment plays the role in illness perception change (βs = 0.544, p < .001): patients without impairment reported decreasing threats of illness, while the ones with it had a similar perception of threat like at baseline. Other biological, psychological, and social factors were partly associated with illness perception after an acute cardiac event but not with perception change after 6 months.

Does Type D predict vital exhaustion in heart failure patients?

2006 ◽  
Author(s):  
H. J. Michielsen ◽  
O. R. F. Smith ◽  
A. A. Schiffer ◽  
J. Denollet
Keyword(s):  
Heart Failure ◽  
Heart Failure Patients ◽  
Vital Exhaustion ◽  
Type D
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