Weak gravitational lensing of the primary scalar hair black hole is proposed within this work. We can figure out the deflection angle of light by applying the Gibbons and Werner approach with a ...primary scalar hair black hole. To do this, we compute the Gaussian curvature and find the deflection angle of the weak field limits by applying Gauss-Bonnet theorem. Furthermore, we compute the deflection angle of light when it comes across both plasma and non-plasma field. We also study how the deflection angle behaves graphically in both cases.
•Using Gauss Bonnet theorem and find deflection angle for non plasma case of scalar hair black hole.•We also compute the deflection angle in the context of plasma medium.•We discuss the graphical behavior of the deflection angle with respect to some specific parameters.
The present study explores the
f
(
R
,
T
)
modified gravity on the basis of observational data for three different compact stars with matter profile as anisotropic fluid without electric charge. In ...this respect, we adopt the well-known Karmarker condition and assume a specific and interesting model for
g
rr
metric potential component which is compatible with this condition. This choice further leads to a viable form of metric component
g
tt
by utilizing the Karmarkar condition. We also present the interior geometry in the reference of Schwarzschild interior and Kohler–Chao cosmological like solutions for
f
(
R
,
T
)
theory. Moreover, we calculate the spacetime constants by using the masses and radii from the observational data of three different compact stars namely 4U 1538-52, LMC X-4 and PSR J1614-2230. In order to explore the viability and stability of the obtained solutions, some physical parameters and properties are presented graphically for all three different compact object models. It is noticed that the parameters
c
and
λ
have some important and considerable role for these solutions. It is concluded that our obtained solutions are physically acceptable, bearing a well-behave nature in
f
(
R
,
T
)
modified gravity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We study the weak gravitational lensing effect of Non-Bocharova-Bronnikov-Melnikov-Bekenstein (BBMB) black hole in new massive conformal gravity. We analyze the deflection angle of light caused by ...new massive conformal gravity by using the Gauss-Bonnet theorem. As a consequence, we obtain the Gaussian optical curvature and calculate the deflection angle of the new massive conformal gravity for spherically balanced space-time with the Gauss-Bonnet theorem. The resultant deflection angle of light in the weak field limits showing that the bending of light is a global and topological phenomenon. Furthermore, we identify the deflection angle of light in the framework of the plasma medium, we also demonstrate the effect of a plasma medium on the deflection of light by non BBMB. In addition, the behavior of the deflection angle by new massive conformal gravity is explicitly shown in the influence of plasma medium and for the non plasma medium.
In this manuscript, we analyze the thermodynamic properties of the Van der Waals black hole. For this purpose, we calculate the geometric mass, Hawking temperature, thermodynamic mass, heat capacity, ...and Gibbs free energy. By studying the properties of mass and temperature, we depict the physical existence of Van der Waals black hole solutions. We calculate the mass of the black hole by using the first law of thermodynamics, then calculate the heat capacity and Gibbs free energy to discuss the phase transition of the Van der Waals black hole. We observe that both the Van der Waals parameters a and b have a significant effect on the thermodynamic properties of the black hole. Additionally, we compute the energy emission rate and show that the emission rate is directly proportional to the Van der Waals parameter. Furthermore, we investigate the effect of quantum gravity on the Van der Waals black hole produced by first-order gravity and also employ the Lagrangian equation, which has been modified by the generalized uncertainty principle (GUP). The tunneling radiation of a Van der Waals black hole is calculated after solving the field equations.
Abstract
This paper aims to discuss the model of compact stars based on spherically symmetric spacetime, with a focus on the gravitational effects of Rastall teleparallel gravity, where
T
represents ...torsion and
λ
represents the Rastall parameter. In this study, we evaluate the spherically symmetric spacetime component
e
a
(
r
)
in terms of
e
b
(
r
)
using the linear equation of state
p
r
=
β
ρ
+
γ
, while the other component
e
b
(
r
)
is assumed from the literature. The paper delves into a detailed analysis of various properties of compact stars such as energy density profile, pressure components, gradients profiles, anisotropic conduct, energy limits, equation of state profiles, velocities of sound profiles, TOV equation profiles, and compactification profile. We use the well-known junction conditions to facilitate the evaluation of the unknown parameters, taking the standard Schwarzschild metric as the outer spacetime. Through detailed analysis in graphical form, we demonstrate that the model showing the anisotropic conduct of stellar objects is viably legitimate, regular, and stable. Overall, the paper provides a comprehensive analysis of the properties of compact stars, which will undoubtedly contribute to our understanding of these astrophysical phenomena.
Abstract
The thermodynamics of black holes (BHs) has had a profound impact on theoretical physics, providing insight into the nature of gravity, the quantum structure of spacetime and the fundamental ...laws governing the Universe. In this study, we investigate thermal geometries and Hawking evaporation of the recently proposed topological dyonic dilaton BH in anti-de Sitter (AdS) space. We consider Rényi entropy and obtain the relations for pressure, heat capacity and Gibbs free energy and observe that the Rényi parameter and dilaton field play a vital role in the phase transition and stability of the BH. Moreover, we use Weinhold, Ruppeiner and Hendi Panahiyah Eslam Momennia models to evaluate the scalar curvature of the BH and find out that the divergence points of the scalar curvature coincides with the zero of specific heat. Finally, using Stefan–Boltzmann law, we determine that the BH without a dilaton field evaporates far more quickly compared to the dilaton BH in AdS space.
We study the long-time asymptotics of the nonlocal Kundu–nonlinear-Schrödinger equation with a decaying initial value. The long-time asymptotics of the solution follow from the nonlinear steepest ...descent method proposed by Deift–Zhou and the Riemann–Hilbert method.
This paper is based on the study of compact stars in the context of electric fields and the nonmetricity effects of gravity. Due to this, we are motivated to build stellar models based on spherically ...symmetric space-time in
f
(
Q
) gravity. The space-time solution is obtained by Durgapal and Bannerji (Phys Rev D 27:328–331,1983) potential along with modified Van der Waals equation of state (EoS)
p
r
=
η
ρ
2
+
β
ρ
γ
ρ
+
1
by introducing a specific form of electric charge function
q
(
r
)
=
k
r
3
. In order to validate our charge model, we used observational data from the literature for celestial objects like Her X-1, 4U 1538-52, SAX J1808.4-3658, and SMC X-1. Furthermore, we have also retrieved the uncharged effects of gravity for the model SMC X-1 by taking
k
=
0
. Our present physical analysis shows that all the obtained features for the present solution are in excellent agreement with the viable model as far as observational data is concerned.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study aims to investigate spherically symmetric anisotropic solutions that describe compact stellar objects in the modified Rastall teleparallel (MRT) theory of gravity. In order to achieve this ...goal, we utilize the Karmarkar condition to evaluate the spherically symmetric components of the line element. We explore the field equations by selecting appropriate off-diagonal tetrad fields for two different scenarios. In the first scenario, we use a hybrid form of
f
(
T
)
=
β
e
mT
T
n
and a linear equation of state (EoS)
p
r
=
ξ
ρ
+
ϕ
, where
0
<
ξ
<
1
, to evaluate
h
(
T
). In the second scenario, we again use a hybrid form of
f
(
T
)
=
β
e
mT
T
n
and a logarithmic form of
h
(
T
)
=
ψ
log
(
ϕ
T
χ
)
. We aim to investigate the possible forms of gravity modifications by evaluating the function for different values of
m
and
n
, reducing the gravity forms to hybrid, power law form, and exponential form. Our findings reveal that the exponential-logarithmic case is unstable in our scenario. To the best of our knowledge, we are the first to attempt to explore compact star models in MRT gravity. After obtaining the field equations, we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models. We utilize observational data, such as the mass and radius of the
P
S
R
J
1416
-
2230
model, to ensure the physical plausibility of our findings.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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