In the context of the late time cosmic acceleration phenomenon, many geometrically modified theories of gravity have been proposed in recent times. In this paper, we have investigated the role of a recently proposed extension of symmetric teleparallel gravity dubbed as f(Q,T) gravity in getting viable cosmological models, where Q and T respectively denote the non-metricity and the trace of energy momentum

In the presence of a real singlet scalar field with Z2 symmetry in addition to the Higgs field in the Standard Model, we analytically investigate all possible one-step and two-step electroweak phase transitions (EWPT) in the high-temperature expansion limit. In particular, we examine the possibility of a first-order phase transition in an intermediate temperature interval of the universe for two-step

We perform null tests of the concordance model, using H(z) measurements that mimic next-generation surveys such as Euclid and the SKA. To this end, we deploy a non-parametric method, so that we make minimal assumptions about the fiducial cosmology as well as the statistical analysis. We produce simulations assuming different cosmological models in order to verify how well we can distinguish between

One of the notable modifications of General Relativity (GR) is the Rastall gravity. We have studied the quasinormal modes of black holes in Rastall gravity in presence of non-linear electrodynamic sources. Here the impacts of cosmological field, dust field, phantom field, quintessence field and radiation field on the quasinormal modes in presence of electrodynamic sources have been investigated. Apart

Since physics of the dark sector components of the Universe is not yet well-understood, the phenomenological studies of non-minimal interaction in the dark sector could possibly pave the way to theoretical and experimental progress in this direction. Therefore, in this work, we intend to explore some features and consequences of a phenomenological interaction in the dark sector. We use the Planck 2018

In the light of the recently observed XENON1T electronic recoil (ER) data, we investigate the possibility of constraining the parameter space of a generic fermionic warm dark matter (WDM), decaying into a standard model (SM) neutrino and a photon. The photon as a decay product, when produced inside the XENON1T chamber, interacts with an electron of a xenon (Xe) atom, leading to a contribution in the

In this paper, we study the late time cosmology of a non-canonical scalar field (k-essence) coupled to a vector field in a Bianchi-I background. Specifically, we study three cases: canonical scalar field (quintessence) with exponential potential as a warm up, the dilatonic ghost condensate, and the Dirac Born Infeld field with exponentials throat and potential. By using a dynamical system approach

We investigate the solutions of black holes in f(T) gravity with nonlinear power-law Maxwell field, where T is the torsion scalar in teleparallelism. In particular, we introduce the Lagrangian with diverse dimensions in which the quadratic polynomial form of f(T) couples with the nonlinear power-law Maxwell field. We explore the leverage of the nonlinear electrodynamics on the space–time behavior.

We propose a minimal framework to address successful quartic inflation, dark matter (DM) production in the early universe and non-vanishing tiny Majorana neutrino mass from a common gravitational origin point of view. In this setup, the quartic inflation is revived successfully via non-minimal coupling of inflaton to gravity while the production of DM takes place from purely gravitational effects through

We carry out a test of the radial acceleration relation (RAR) for a sample of 10 dynamically relaxed and cool-core galaxy clusters imaged by the Chandra X-ray telescope, which was studied in Giles et al. (2016). For this sample, we observe that the best-fit RAR shows a very tight residual scatter equal to 0.09 dex. We obtain an acceleration scale of 1.59×10−9 m/s2, which is about an order of magnitude

We analytically derive a class of non-singular, static and spherically symmetric topological black hole metrics in F(R)-gravity. These have not a de Sitter core at their centre, as most model in standard General Relativity. We study the geometric properties and the motion of test particles around these objects. Since they have two horizons, the inner being of Cauchy type, we focus on the problem of

In this work we propose a new coupled generalized three-form dark energy model, in which dark energy are represented by a three-form field and dark matter are represented by point particles that can be regarded as dust. We first perform a dynamical analysis on the new model and obtain four fixed points, including a saddle point representing a radiation dominated Universe, a saddle point representing

The concordance of the ΛCDM cosmological model in light of current observations has been the subject of an intense debate in recent months. The 2018 Planck Cosmic Microwave Background (CMB) temperature anisotropy power spectrum measurements appear at face value to favour a spatially closed Universe with curvature parameter ΩK<0. This preference disappears if Baryon Acoustic Oscillation (BAO) measurements

In this paper, we extend previous works on the relation between mass and the inner slope in dark matter density profiles. We calculate that relation in the mass range going from dwarf galaxies to cluster of galaxies. This was done thanks to a modelling of energy transfer via SN and AGN feedback, as well as via dynamical friction of baryon clumps. We show that, in the mass range above galaxy masses

Present analysis dedicated to the dynamical investigation of models of holographic dark energy using FLRW cosmological model in the context of modified gravity in which Lagrangian be the arbitrary function of the trace of the non-metricity tensor Q say f(Q) gravity where the nonmetricity Q is responsible for the gravitational interaction. We govern the features of the derived cosmological model in

In this note, we explore the thermodynamic properties of the universe in the background of the generalized energy–momentum-squared gravity. We derive the energy density of matter from the non-standard continuity equation and use it in our analysis. We consider two types of models depending on the nature of coupling between curvature and matter and perform thermodynamic analysis on them using the cosmic

The Gaia map of the Milky Way reveals a pair of triangular features at nearly symmetric locations on opposite sides of the Galactic Center. In this paper we explore the implications of these features assuming they are manifestations of a caustic ring in the dark matter distribution of the Milky Way halo. The existence of a series of such rings is predicted by the Caustic Ring Model. The model’s phase-space

This paper explores the dynamics of evolving cluster of stars in the presences of exotic matter. The f(R) theory is used to presume exotic terms for evolution scenario. We use structure scalars as evolution parameters to explore dynamics of spherically symmetric distribution of evolving cluster of stars. We consider Starobinsky model, f(R)=R+ϵR2 and study different evolution modes having features like

We consider the holographic Friedman–Robertson–Walker (hFRW) universe on the 4-dimensional membrane embedded in the 5-dimensional bulk spacetime and fit the parameters with the observational data. In order to fully account for the phenomenology of this scenario, we consider the models with the brane cosmological constant and the negative bulk cosmological constant. The contribution from the bulk is

In the recently suggested non-standard, quasi-molecular mechanism of recombination, the presence of neighboring proton increases the ionization energy and decreases the final recombination rate of hydrogen. Both these two effects can lead to the larger value of the present expansion rate of the universe obtained using CMB data and standard cosmological model, and thus are able to reduce or resolve

In this paper, we investigate the four-dimensional Einstein–Gauss–Bonnet black hole. The thermodynamic variables and equations of state of black holes are obtained in terms of a new parameterization. We discuss a formulation of the van der Waals equation by studying the effects of the temperature on P−V isotherms. We show the influence of the Cauchy horizon on the thermodynamic parameters. We prove

In this work, we study the potential of the Cherenkov Telescope Array (CTA) for the detection of Galactic dark matter (DM) subhalos. We focus on low-mass subhalos that do not host any baryonic content and therefore lack any multiwavelength counterpart. If the DM is made of weakly interacting massive particles (WIMPs), these dark subhalos may thus appear in the gamma-ray sky as unidentified sources

With the goal of studying the cosmological constant (CC) problem, we present an exhaustive analysis of unimodular gravity as a possible candidate to resolve the CC origin and with this, the current Universe acceleration. In this theory, a correction constant (CC-like) in the field equations sources the late cosmic acceleration. This constant is related to a new parameter, zini, which is interpreted

Gravitational waves can probe the existence of planetary-mass primordial black holes. Considering a mass range of [10−7−10−2]M⊙, inspiraling primordial black holes could emit either continuous gravitational waves, quasi-monochromatic signals that last for many years, or transient continuous waves, signals whose frequency evolution follows a power law and last for O(hours-months). We show that primordial

A general equation of state is considered for analyzing the possible behaviors for (Early) dark energy that alleviates the Hubble parameter tension problem. By departing from the possible evolution for the (Early) dark energy density and the corresponding dynamical equations, the equation of state is obtained, which allow us to analyze qualitatively the cosmological evolution and the dominance of each

We investigate Einstein-Æther gravity in light of the recent Event Horizon Telescope (EHT) observations of the M87*. The shape and size of the observed black hole shadow contains information of the geometry in its vicinity, and thus one can consider it as a potential probe to investigate different gravitational theories, since the involved calculation framework is enriched with different size-rotation

Three different approaches show that, contrary to a longstanding conviction older than 160 years, the advance of Mercury’s perihelion can be achieved in Newtonian gravity with a very high precision by correctly analyzing the situation without neglecting Mercury’s mass. General relativity remains more precise than Newtonian physics, but Newtonian framework is more powerful than researchers and astronomers

In this paper, the thermodynamics and the stability of horizon of the charged AdS black hole surrounded by quintessence and cloud of strings in d-dimensional spacetime are studied via the scalar field scattering and the charged particle absorption. The cosmological constant is interpreted as the thermodynamic pressure in the black hole. During the study, we consider the case where the energy of the

The implications of thermal geometries on Brane-World black hole (consisting of cosmological and dark matter effects) will be investigated by extracting the stability conditions (small and large roots) and divergences. To achieve this, we develop the temperature and heat capacity with respect to horizon radius, cosmological and dark matter parameters, respectively, which help in analyzing the small

We consider a cosmological model with dark matter in the form of ∼10−12M⊙ primordial black holes in dense weakly relativistic clusters with masses 18–560M⊙. It is shown that during the multiple collisions of the black holes the ∼10% of the initial cluster mass can be transformed into gravitational waves in the time interval from recombination to the redshifts z≥10. At the recombination epoch, the density

Quantum-effective gravity must lead to a regularized cosmology and thereby by itself source and regulate the high energy inflaton fields required for an appropriate inflationary beginning of the Universe. Pursuing this premise, we involve in the generic code of extended theories of gravity in conceiving semi-classical imprinting of quantum effects into gravitation. Hence, we prescribe a general semi-classical

We study the gravitational waves phenomena for generalized Chaplygin gas, variable modified Chaplygin gas and some parametrizations of dark energy models. Motivated by their works, here we consider the Friedmann–Robertson–Walker (FRW) model of the non-flat Universe in the presence of dark matter with dark energy and we investigate the gravitational waves phenomena for some other candidates of dark

Purely kinetic k-essence models have been shown in the literature to be a field theory equivalent of barotropic fluid models of dark energy or dark matter–dark energy unification. In the modeling framework where the speed of sound squared of a barotropic fluid is modeled as a function of its Equation of State parameter, a systematic procedure of obtaining the Lagrangian density of an equivalent purely

Improvement of the classical gravity with the running gravitational coupling obtained from asymptotically safe gravity, is a good way of considering the effects of quantum gravity. This is usually done for metric theories of gravity. Here we investigate the effects of such an improvement for pure affine theories of gravity. To motivate the approach, we first consider the effects of quantum improvement

The matter–antimatter asymmetry through baryogenesis (and generalized baryogenesis interaction) mechanism for well-known models of f(R,G) gravity (where R,G represent the Ricci scalar curvature and Gauss–Bonnet topological invariant) and f(G,T) (T denotes the trace of the energy momentum tensor) is being examined. This mechanism is based on the charge-parity (CP) violating interaction between the derivative

We consider a non-canonic field in the context of Starobinsky inflation. We work in Einstein-frame. In this frame, the gravitational part of the action is equivalent to the Hilbert–Einstein action, plus a scalar field called scalaron. We investigate a model with a heavy scalaron trapped at the effective potential minimum, where its fluctuations are negligible. To be more explicit, we consider a Dirac–Born–Infeld

We present here a quantitative estimate of the impact of uncertainties of astrophysical nature on the determination of the dark matter distribution within our Galaxy, the Milky Way. Based on an update of a previous analysis, this work is motivated by recent new determinations of astrophysical quantities of relevance – such as the Galactic parameters (R0, V0) – from the GRAVITY collaboration and the

In the present paper, we investigate the required anisotropy of an exact regular Bardeen black hole characterized by its mass M and the nonlinear parameter β in anti-de sitter spacetime with a static anisotropic matter field. We also show that the relative pressure anisotropy, equation of state and the pressure depends on the radial coordinate, reflecting the required anisotropy for Bardeen black hole

The multi-messenger observation of GW170817 enabled the first historic measurement of the Hubble constant via a standard siren, so-called in analogy to standard candles that enabled the measurement of the luminosity distance versus redshift relationship at small redshift. In the next decades, third-generation observatories are expected to detect hundreds to thousand of gravitational wave events from

After reionisation, the 21 cm emission line of neutral hydrogen within galaxies provides a tracer of dark matter. Next-generation intensity mapping surveys, with the SKA and other radio telescopes, will cover large sky areas and a wide range of redshifts, facilitating their use as probes of primordial non-Gaussianity. Previous works have shown that the bispectrum can achieve tight constraints on primordial

The observation of strongly lensed Type Ia supernovae enables both the luminosity and angular diameter distance to a source to be measured simultaneously using a single observation. This feature can be used to measure the distance duality parameter η(z) without relying on multiple datasets and cosmological assumptions to reconstruct the relation between angular and luminosity distances. In this paper

We test the cosmological implications of a varying absolute magnitude of Type Ia supernovae using the Pantheon compilation, by reconstructing different phenomenological approaches that could justify a varying absolute magnitude, but also approaches based on cosmic voids, modified gravity models and a binning scheme. In all the cases considered in this work, we find good agreement with the expected

We consider a specific dark energy model, which only includes the Lagrangian up to the cubic order in terms of the vector field self-interactions in the generalized Proca theory. We examine the cosmological parameters in the model by using the data sets of CMB and CMB+HST, respectively. In particular, the Hubble constant is found to be H0=71.80−0.72+1.07 (72.48−0.60+0.72) kms−1Mpc−1 at 68% C.L. with

In this paper, we will consider cosmological implications of the Maxwell theory coupled to a non-local U(1)-symmetric term. It is well-known that the theory in flat space–time, reduces to the Proca theory. However, it will be shown that in curved space–time the resulting theory will differ from the coupled Einstein–Proca system. The cosmological perturbations on top of the de Sitter space–time is also

In this article, we have investigated the role of bulk viscosity to study the accelerated expansion of the universe in the framework of modified f(Q) gravity. The gravitational action in this modified gravity theory has the form f(Q), where Q denote the non-metricity scalar. In the present manuscript, we have considered a bulk viscous matter-dominated cosmological model with the bulk viscosity coefficient

We assume a dark U(1)D symmetric hidden sector and explore its possible content such that neutrino mass and Dark Matter are generated through the scotogenic mechanism. The hidden sector is considered analogue to the Standard Model, namely the charge assignment of hidden fermions is chiral and anomaly-free. Moreover, U(1)D is assumed broken by an only Higgs singlet that also generates masses to all

In the present work we present, for the first time ever, the exact configuration integral entering the partition function Z that allows for a statistical mechanics treatment of galactic clustering. Thus, the general distribution function and the general clustering parameter for point mass systems is obtained from a grand canonical ensemble discussion. Such distribution is also approximated starting

We perform correct and reasonable cosmological constraints on the newly proposed 4D Gauss–Bonnet gravity. Using the joint constraint from cosmic microwave background, baryon acoustic oscillations, Type Ia supernovae, cosmic chronometers and redshift space distortions, we obtain, so far, the strongest constraint α̃=(1.2±5.2)×10−17, namely α=(2.69±11.67)×1048 eV−2, among various observational limitations

We use a combination of observational data in order to reconstruct the free function of f(T) gravity in a model-independent manner. Starting from the data-driven determined dark-energy equation-of-state parameter we are able to reconstruct the f(T) form. The obtained function is consistent with the standard ΛCDM cosmology within 1σ confidence level, however the best-fit value experiences oscillatory

We investigate Euclidean wormholes in Gauss–Bonnet-dilaton gravity to explain the creation of the universe from nothing. We considered two types of dilaton couplings (i.e., the string-inspired model and the Gaussian model) and we obtained qualitatively similar results. There can exist Euclidean wormholes that explain the possible origin of our universe, where the dilaton field is located over the barrier

With the recent data from the first year of the Dark Energy Survey (DES Y1), we attempt to probe whether there is new physics beyond the standard cosmology and to reconcile the σ8 tension between the DES Y1 and Planck datasets in three alternative cosmological models. Combining the galaxy clustering and weak gravitational lensing data from the DES Y1 with other cosmological observations including cosmic

We pioneer the black hole mass gap as a powerful new tool for constraining new particles. A new particle that couples to the Standard Model – such as an axion – acts as an additional source of loss in the cores of population-III stars, suppressing mass lost due to winds and quenching the pair-instability. This results in heavier astrophysical black holes. As an example, using stellar simulations we

In an alternative dark matter scenario, it is assumed that there exist two species of dark matter: a heavy dark matter particle (HDM) with the mass of O(TeV) which is generated in early universe and a lighter dark matter particle (LDM) which is a relativistic product due to the decay of HDM. HDMs, captured by the earth, decay to high energy LDMs, and these particles can be measured by km3 neutrino

In this paper, we study a triad of inhomogeneous scalar fields, known as ”solid”, as a source of homogeneous but anisotropic dark energy. By using a dynamical system approach, we find that anisotropic accelerated solutions can be realized as attractor points for suitable choices of the parameters of the model. We complement the dynamical analysis with a numerical solution whose initial conditions are

Within the framework of Unimodular Gravity, we consider non-gravitational interactions between dark matter and dark energy. Particularly, we describe such interactions in the dark sector by considering diffusion models that couple the cold dark matter fluid with the dark energy component, where the latter has the form of a variable cosmological “constant”. For the first time, we solve the cosmological

In this work, we explore the phenomenon of cosmic evolution using curved FLRW space–time bounded by apparent horizon with a specific holographic cut-off. To this end, we use the framework of Rastall gravity (RG) and universe is assumed to be consists of interacting/ non-interacting dark energy (DE) and dark matter (DM). In both scenarios, we evaluate exact solutions of the dynamical equations and constraint

In this paper, we investigate the behavior of charged anisotropic solutions for a static sphere in the background of self-interacting Brans–Dicke theory. The spherical solutions are devised from known isotropic distributions by adding a source in the action. Deformations are induced in temporal and radial metric functions to decompose the field equations into two sets. We employ the metric potentials

This article discusses a dark energy cosmological model in the standard theory of gravity - general relativity with a broad scalar field as a source. Exact solutions of Einstein’s field equations are derived by considering a particular form of deceleration parameter q, which shows a smooth transition from decelerated to accelerated phase in the evolution of the universe. The external datasets such

We inspect the possibility that neutron star interiors are a mixture of ordinary matter and mirror dark matter. This is a scenario that can be naturally envisaged according to well studied accretion mechanisms, including the Bondi–Hoyle one. We show that the inclusion of mirror dark matter in neutron star models lowers the maximum neutron star mass for a given equation of state, and that it decreases

In this work we shall study the implications of a subclass of E-models cosmological attractors, namely of a-attractors, on hydrodynamically stable slowly rotating neutron stars. Specifically, we shall present the Jordan frame theory of the a-attractors, and by using a conformal transformation we shall derive the Einstein frame theory. We discuss the inflationary context of a-attractors in order to