We present an efficient numerical code and conduct, for the first time, a null and model-independent CMB test of statistical isotropy using Multipole Vectors (MVs) at all scales. Because MVs are insensitive to the angular power spectrum Cℓ, our results are independent from the assumed cosmological model. We avoid a posteriori choices and use a pre-defined range of scales ℓ∈[2,30], ℓ∈[2,600] and ℓ∈[2

In this paper, we construct anisotropic spherical solutions from known isotropic solutions through extended gravitational decoupling method in the background of self-interacting Brans–Dicke theory. The field equations are decoupled into two sets by applying geometric deformations on radial as well as temporal metric components. The first array corresponds to isotropic fluid while influence of the anisotropic

This paper is devoted to develop compact stellar configuration and to evaluate exact interior solutions in the background of f(T,T) gravity, where T be the torsion scalar and T be the trace of energy momentum tensor. We develop a new set up for embedding class I model under well-known Karmarkar condition for LMC X-4 and Vela X-1 compact stars using specific linear function f(T,T)=αT(r)+βT(r)+Φ, where

We study neutrino oscillations in a medium of dark matter which generalizes the standard matter effect. A formula is derived to describe the effect of medium and its mediator to neutrinos. Neutrinos and anti-neutrinos receive opposite contributions from asymmetric distribution of (dark) matter and anti-matter, and thus it could appear in precision measurements of neutrino or anti-neutrino oscillations

In this work we shall present models of F(R) gravity which realize in a unified way the inflationary era along with a post-inflationary early dark energy era, with the late-time dark energy era. We shall use two approach methods in order to realize the unified cosmological eras, firstly we specify a Hubble rate which may describe the three distinct acceleration eras, and then by using well known F(R)

Global cosmic strings are generically predicted in particle physics beyond the Standard Model, e.g., a post-inflationary global U(1) symmetry breaking which may associate with axion-like dark matter. We demonstrate that although subdominant to Goldstone emission, gravitational waves (GWs) radiated from global strings can be observable with current/future GW detectors. The frequency spectrum of such

We consider gravitational collapse in the recently proposed 4D limit of Einstein–Gauss–Bonnet gravity. We show that for collapse of a sphere made of homogeneous dust the process is qualitatively similar to the case of pure Einstein’s gravity. The singularity forms as the endstate of collapse and it is trapped behind the horizon at all times. However, and differently from Einstein’s theory, as a consequence

This paper encompasses a set of stellar equations that administer the formation and evolution of self-gravitating, dissipative spherically symmetric fluid distributions having anisotropic stresses in the presence of electromagnetic field. The Riemann tensor is split orthogonally to procure five scalar functions named as structure scalars which are then utilized in the stellar equations. It is shown

In this paper, we study the thermodynamics and statistics of the galaxies clustering affected by the dynamical dark energy. We consider two important dark energy models based on time dependent equation of state to evaluate the gravitational partition function. In the first model, we consider barotropic dark energy with time dependent equation of state. However, in the second model, we consider various

An effective Lagrangian approach, partly inspired by Quantum Loop Cosmology (QLC), is presented and formulated in a non flat FLRW space–times, making use of modified gravitational models. The models considered are non generic, and their choice is dictated by the necessity to have at least second order differential equations of motion in a non flat FLRW space–time. This is accomplished by a class of

In this paper, we study thermodynamics, quasi-normal modes and thermal fluctuations of a charged black hole with Weyl corrections. We first obtain thermodynamic quantities such as Hawking temperature, entropy, and heat capacity for non-rotating as well as rotating versions of this black hole. We also evaluate temperature through quantum tunneling mechanism which is exactly the same as found through

In this paper, we introduce static black hole with accounting of f(R) gravity. First, we study thermal properties and phase transition of corresponding black hole. Also, here we do correction to the entropy and temperature at same time in above mentioned black hole. Second step, we obtain such corrected thermodynamical properties and study the P−V critically and phase transition. We also investigate

In this paper, we estimate the cross-correlation power spectra between the Planck 2018 cosmic microwave background (CMB) temperature anisotropy map and the unresolved γ-ray background (UGRB) from the 9-years Fermi-Large Area Telescope (LAT) data. In this analysis, we use up to nine energy bins over a wide energy range of [0.631, 1000] GeV from the Fermi-LAT UGRB data. Firstly, we find that the Fermi

In this paper, we investigate irregularities in a cylindrical self-gravitating system which contains the properties of an imperfect matter and electromagnetic field. For f(R,T,Q) theory, in which R represents the Ricci scalar and T shows the trace of matter stress–energy tensor while Q≡RγδTγδ, the field equations containing electric charge, mass functions and Darmois junction conditions at the hypersurface

We present the first application to real data from the BOSS DR12 dataset of the Extractor procedure (Noda et al., 2017, Nishimichi et al., 2018) to determine the acoustic scale imprinted on Baryonic Acoustic Oscillations (BAO). We show that, being largely insensitive to the broadband shape of the Power Spectrum, this procedure requires a lower number of nuisance parameters than those used by the BOSS

We perform a reconstruction of the coupling function between vacuum energy and geodesic cold dark matter using the latest observational data. We bin the interaction in seventeen redshift bins but use a correlation prior to prevent rapid, unphysical oscillations in the coupling function. This prior also serves to eliminate any dependence of the reconstruction on the binning method. We use two different

In the present work, we investigate the possibility of obtaining stellar interiors for static self-gravitating systems describing an anisotropic matter distribution in the framework of Rastall gravity through gravitational decoupling by means of minimal geometric deformation approach. Due to Rastall gravity breaks down the minimal coupling matter principle, we have provided an exhaustive explanation

In this paper we employ Tolman VII solution with exotic matter that may be present in the extremely dense core of compact objects. The Tolman VII solution, an exact analytic solution to the spherically symmetric, static Einstein field equations with a perfect fluid source, has many characteristics that make it interesting for modeling high density stellar astronomical objects. For our purpose we use

The observed value of the cosmological constant poses large theoretical problems. We find that topology of the Universe provides a natural source for it. Restricting dynamically an Einstein–Cartan gravity to General Relativity in our observed Universe allows topological invariants to induce an effective cosmological constant from dynamical quintessence-like topological fields. Its evaluation through

We show that fundamental plane of elliptical galaxies can be used to obtain observational constraints on metric theories of gravity. Being it connected to global properties of ellipticals, it can fix parameters of modified gravity. Specifically, we use fundamental plane to constrain modified theories of gravity with Yukawa-like corrections which commonly emerge in the post-Newtonian limit. After giving

Gravitational microlensing is a key probe of the nature of dark matter and its distribution on the smallest scales. For many practical purposes, confronting theory to observation requires to model the probability that a light source is highly amplified by many-lens systems. This article reviews four simple analytic models of the amplification probability distribution, based on different approximations:

Two new fast single radio bursts FRB 180924 and FRB 190523 well localized to massive galaxies have opened a new window to probe and characterize how cosmic baryons are allocated between galaxies, their surroundings and intergalactic medium. We are motivated by testing Einstein’s weak equivalence principle with these two cosmic transients which have accurate redshifts. Using photons with different energies

This paper is devoted to present new definition of complexity factor for static cylindrically symmetric matter configurations in f(R,T,RμνTμν) gravity. For this purpose, we have considered irrotational static cylindrical spacetime coupled with a locally anisotropic relativistic fluid. After formulating gravitational field and conservation equations, we have performed orthogonal splitting of the Riemann

We study the behaviour of massive particles under different potentials near a static spherical black hole. Our purposes are to apply the Hamilton–Jacobi method for this study and to investigate the effects of a minimal length on the motion of particles in unstable equilibrium near the black hole horizon by deformation of a canonical position–momentum commutation relation. We also obtain the equation

Two distinct perturbative approaches have been recently formulated within General Relativity, arguing for the screening of gravity in the ΛCDM Universe. In this paper we compare them and show that the offered screening concepts, each characterized by its own interaction range, can peacefully coexist. Accordingly, we advance a united scheme, determining the gravitational potential at all scales, including

In this paper, we discuss some feasible features of gravastar that was firstly demonstrated by Mazur and Mottola. It is already established that gravastar associates the de-Sitter spacetime in its inner sector with the Schwarzschild geometry at its exterior through the thin shell possessing the ultra-relativistic matter. We have explored the singularity free spherical model with a particular equation

We use recent 36 observational Hubble data (OHD) in the redshift range 0.07≤z≤2.36, latest “joint light curves” (JLA) sample, comprised of 740 type Ia supernovae (SNIa) in the redshift range 0.01≤z≤1.30, and their joint combination datasets to constrain anisotropic Bianchi type I (BI) dark energy (DE) model. To estimate model parameters, we apply Hamiltonian Monte Carlo technique. We also compute the

In this work we shall study the late-time behavior of k-Essence f(R) gravity without scalar potential, in the presence of matter and radiation perfect fluids. We quantify the late-time study by using the statefinder function YH(z)=ρDEρm(0), which is a function of the redshift and of the Hubble rate. By appropriately rewriting the Friedmann equation in terms of the redshift and of the function YH(z)

This paper is based on analysis of cosmological parameters and thermodynamics in a modified theory of gravity whose action contains linear coupling of Ricci scalar R and a second degree term of its covariant derivative. The Friedmann equations obtained in result of considering the spatially flat FRW universe filled with dark energy and pressureless matter, are of fifth-order in the Hubble function

Teleparallel gravity is a modified theory of gravity for which the Ricci scalar R of the underlying geometry in the action is replaced by an arbitrary functional form of torsion scalar T. In doing so, cosmology in f(T) gravity becomes greatly simplified owing to the fact that T contains only the first derivatives of the vierbeins. The article exploits this appealing nature of f(T) gravity and present

In this study, we provide an alternatively reformulated interpretation of Gibbons–Hawking radiation as well as inflation. By using a spacetime quantization procedure, proposed recently by L.C. Céleri et al., in anti-de Sitter space we show that Gibbons–Hawking radiation is an intrinsic property of the concerned space, that arises due to the existence of a scalar field whose quanta “carry” a length

A general formalism developed few years ago to model polytropic Newtonian stars with anisotropic pressure is applied to model stars for which, both, radial and tangential pressure satisfy polytropic equations of state. We obtain the corresponding Lane–Emden equation, and integrate it for a wide range of values of the parameters, thereby illustrating the effects of the pressure anisotropy on stellar

We investigate the quantum evolution of the universe in the presence of two types of dark energies. First, we consider the phantom class (ω<−1) which would be responsible for a super-accelerated cosmic expansion, and then we apply the procedure to an ordinary Λ>0 vacuum (ω=−1). This is done by analytically solving the Wheeler-DeWitt equation with ordering term (WdW) in the cosmology of Friedmann-Robertson-Walker

A wavelike solution for the non-relativistic universal dark matter (wave-DM) is rapidly gaining interest, following pioneering simulations of cosmic structure as an interference pattern of coherently oscillating bosons. A prominent solitonic standing wave is predicted at the center of every galaxy, representing the ground state solution of the coupled Schrödinger–Poisson equations, and it has been

This work is devoted to study the analytical and regular solutions of a particular self-gravitating object (i.e., gravastar) in a particular theory of gravity. We derive the corresponding field equations in the presence of effective energy momentum tensor associated with the perfect fluid configuration of a spherical system. We then describe the mathematical formulations of the three respective regions

In this article, we have studied a cylindrically symmetric self-gravitating dynamical object via complexity factor which is obtained through orthogonal splitting of Reimann tensor in f(R,T) theory of gravity. Our study is based on the definition of complexity for dynamical sources, proposed by Herrera et al. (2019). We actually want to analyze the behavior of complexity factor for cylindrically symmetric

The present paper is devoted to the study of bouncing cosmology in f(R,T) modified gravity where we presume f(R,T)=R+2λT, with R the Ricci scalar, T the trace of energy–momentum tensor and λ the model parameter. We present here a novel parametrization of Hubble parameter which is apt in representing a successful bouncing scenario undergoing no singularity. We proceed to present a complete analysis

We study the covariance in the angular power spectrum estimates of CMB fluctuations when the primordial fluctuations are non-Gaussian. The non-Gaussian covariance comes from a nonzero connected four-point correlation function – or the trispectrum in Fourier space – and can be large when long-wavelength (super-CMB) modes are strongly coupled to short-wavelength modes. The effect of such non-Gaussian

In this work we shall study ghost-free non-local F(R) gravity models. Firstly we shall demonstrate how the ghost degrees of freedom may occur in the non-local F(R) gravity models, and accordingly we shall modify appropriately the gravitational action of non-local F(R) gravity models in order to eliminate the ghosts. Also we shall investigate how the (anti-)de Sitter and the Minkowski spacetime cosmological

Whereas the nature of dark components in the Universe remains unknown, alternative models of gravity have been developed to offer a geometric explanation to the origin of such components. In this work we use the Minimal Geometric Deformation approach to study extensions of the theory of General Relativity in a cosmological context. This is possible since such approach allows the decoupling of gravitational

Under the belief that the universe should be multi-feature and informative, we employ a model-by-model comparison method to explore the possibly largest upper bound on the swampland constant c. Considering the interacting quintessence dark energy as the comparison model, we constrain the large parameter space interacting dark energy model, a 12-parameter extension to the ΛCDM cosmology, in light of

Gravitational-wave detectors on earth have detected gravitational waves from merging compact objects in the local Universe. In future we will detect gravitational waves from higher-redshift sources, which trace the high-redshift structure formation history. That is, by observing high-redshift gravitational-wave events we will be able to probe structure formation history. This will provide additional

We study the dark matter (DM) surface density using the SPARC sample and compare it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in

We derive a Higgs inflationary model in the context of a complex geometrical scalar-tensor theory of gravity. In this model the Higgs inflaton scalar field has geometrical origin playing the role of the Weyl scalar field in the original non-riemannian background geometry. The energy scale enough to generate inflation from the Higgs energy scale is achieved due to the compatibility of the theory with

In this manuscript we consider the traversable wormhole solutions in teleparallel gravity formalism with and without Rastall constraint on stress–energy tensor of dark energy. We have studied the isotropic and non-isotropic form of stress–energy tensor of dark energy which the equation of state (EoS) between density and the radial components of pressure is used. This work is done for a diagonal tetrad

The center of attention of this article is to examine the dynamics of conformally flat anisotropic spheres in the background of electromagnetic field satisfying the polytropic equations of state. We have resorted to the general framework developed in Herrera and Barreto (2013) that helps to inspect the rudimentary attributes of polytropic spheres in the framework of a particular f(R) gravity. We explored

Many studies point out that there exists some tight correlations between dark matter and baryonic matter at different radii in galaxies. However, similar tight correlations can only be found in galaxy clusters for large radii. Here we report extremely tight correlations between the gravitational mass Mgrav and hot gas mass Mgas in galaxy clusters at the hot gas core radius rc and at 2rc (i.e. Mgrav(rc)

We show that the pulsar mass depends on the environment, and that it decreases going towards the centre of the Milky Way. This is due to two combined effects, the capture and accumulation of self-interacting, non-annihilating dark matter by pulsars, and the increase of the dark matter density going towards the galactic centre. We show that mass decrease depends both on the density profile of dark matter

A decomposed generalised Chaplygin gas (gCg) with energy flux from dark energy to dark matter, represented by a negative value for the gas parameter α, is shown to alleviate the tension between EDGES data and the cosmological standard model. Using EDGES data and employing a Bayesian statistical analysis, the agreement with the standard model is only marginal. However, if α is negative enough the gCg

The Global Network of Optical Magnetometers for Exotic physics searches (GNOME) is a network of time-synchronized, geographically separated, optically pumped atomic magnetometers that is being used to search for correlated transient signals heralding exotic physics. GNOME is sensitive to exotic couplings of atomic spins to certain classes of dark matter candidates, such as axions. This work presents

We study the structure of spherically symmetric and static objects in the presence of a nonminimally coupled scalar field having a potential of the form V(ϕ)=−μ2ϕ2∕2+λϕ4∕4. We numerically solve equations of the system using two different realistic equations of state for neutron matter and give the mass-radius relations as well as the radial profiles of the scalar field, densities and the mass function

In this paper, we investigate complex-valued Euclidean wormholes in the Starobinsky inflation. Due to the properties of the concave inflaton potential, the classicality condition at both ends of the wormhole can be satisfied, as long as the initial condition of the inflaton field is such that it is located sufficiently close to the hilltop. We compare the probabilities of classicalized wormholes with

We revisit the dark degeneracy that arises from the Einstein equations relating geometry to the total cosmic substratum but not resolving its individual components separately. We establish the explicit conditions for the dark degeneracy in the fluid description of the dark sector. At the background level, this degeneracy can be formally understood in terms of a unified dark sector Equation of State

This manuscript aims to discuss the factors holding in/stability of axially symmetric compact system with anisotropic environment in the background of f(R,T) gravity, where R is invariant Ricci curvature and T stands for trace of energy–momentum tensor. We constituted field and conservation equations in the background of f(R,T) gravity. To establish the collapse equation, we make use of perturbation

Motivated by previous studies in literature about the potential importance of relativistic corrections to galaxy cluster hydrostatic masses, we calculate the masses of 12 relaxed clusters (with Chandra X-ray data) using the Tolman–Oppenheimer–Volkov (TOV) equation of hydrostatic equilibrium and the ideal gas equation of state. Analytical formulae for gas density and temperature profiles for these clusters

The manifestation of the dark Universe begun with unexpected large-scale astronomical observations. Here we are investigating the possible origin of small-scale anomalies, like that of the annually observed temperature anomalies in the stratosphere (38.5 – 47.5 km). Unexpectedly within known physics, we observe a planetary relationship of the daily stratospheric temperature distribution. Interestingly

The beta-function formalism is being used to study the constant-roll inflation in k-essence models. Assuming the second slow-roll parameter as a constant leads to a first-order differential equation for β-function which much easier to solve and find a solution than the second (non-linear) order equation that we have in the corresponding standard constant-roll inflation. Many cosmological models are

Observations have indicated that we do not see neutron stars (NS) of mass near the theoretical upper limit as predicted. Here we invoke the role of dark matter (DM) particles in star formation, and their role in lowering the mass of remnants eventually formed from these stars. Massive stars can capture DM particles more effectively than the lower mass stars, thus further softening the equation of state

In this work, we extend the work of gravastars to analyze the role of electromagnetic field in f(R,T) gravity. We consider the irrotational cylindrically symmetric geometry and established the f(R,T) field equations and conservation laws. After considering charged exterior geometry, the mathematical quantities for evaluating Israel junction conditions are being calculated. The mass of the gravastar-like

Adopting the Tolman–Oppenheimer–Volkoff formalism, we propose a new analytical solution for a static and spherically symmetric black hole where the cosmological constant is generalized to a non-isotropic Anton–Schmidt fluid acting as a unified dark energy–dark matter source. Our novel result can describe a black hole in energetic equilibrium with the surrounding universe. We thus investigate the interplay