By applying the Newman–Janis Algorithm, we investigate optical behaviors of rotating Ayón–Beato–García black holes in four-dimensional Einstein Gauss–Bonnet Gravity. Exploiting Hamilton–Jacobi mechanism, first obtain needed null geodesic equations motion. We then provide analytic and numerical methods to study associated aspect for certain regions involved moduli space. Concretely, analyze examine shadow terms one-dimensional real closed curves. Particularly, find various shapes including...

In this paper, we first study the brane cosmological behaviors of Starobinsky inflationary model. particular, compute associated parameters including perturbation ones. Among others, find that spectral index and tensor-to-scalar ratio are in a good agreement with Planck observational BICEP/Keck data. Varying five-dimensional mass [Formula: see text] values, investigate thermal behaviors. Concretely, calculate examine reheating parameters. For specific value stringy parameter, provide...

In this paper, we investigate an inflation scenario and dark energy in a scaled gravity, [Formula: see text] where is dimensionless gravity parameter, with kinetic term. To reduce the associated moduli space, implement such parameter specific scalar potential given by text]. By computing relevant cosmological observables including spectral index tensor-to-scalar ratio via slow-roll analysis, provide certain inflationary constraints on from Planck observational recent released BICEP/Keck...

We investigate cosmological inflation models from Randall–Sundrum brane physics. In particular, we examine certain parameters for two potentials, being a logarithmical one and open string tachyonic (OSTI). the presence of tension, give scalar field constraints providing inflationary matching with Planck results. Then, discuss reheating phase such models. Precisely, temperature depends on potential forms. Among others, find that OSTI provides small temperatures, supported by GUT scales.

In this paper, we construct the slowly rotating case of an asymptotically flat supermassive black hole embedded in dark matter using Newman-Janis procedure. Our analysis is carried with respect to involved parameters including halo total mass $M$ and galaxy's lengthscale $a_0$. Concretly, investigate impact on effective potential photon sphere. particular, find that $a_0$ controles such values. Indeed, for low values, decreases values significantly while high diluted. Regarding shadow...

Abstract We explore the shadows and photon rings casted by black holes in cavity. Placing observer inside such an isothermal background, we examine influence of cavity temperature T cav charge Q on involved optical features. After studying effect horizon radius varying , investigate thermal behaviors hole a For fixed values, find that shadow r s increases decreasing . Varying temperature, discuss associated energy emission rate. that, show curves - plane share similarities with G Anti de...

We propose and investigate inflationary models dark energy in a scaled gravity, R + βR where β is dimensionless gravity parameter, with kinetic terms coupled to the scalar field potential via moduli space. To start, we find equations of motion by considering generic potential. Using slow-roll formalism, compute cosmological quantities proposed model. Implementing gravityparameter specific given modelingthe coupling between study relevant observables such as spectral index ns tensor-to-scalar...

We explore the shadows and photon rings casted by black holes in cavity. Placing observer inside such an isothermal background, we examine influence of cavity temperature T_{cav} charge Q on involved optical aspect. After studying effect horizon radius varying Q, investigate thermal behaviors hole a For fixed values, find that shadow r_s increases decreasing T_{cav}. Varying temperture, discuss associated energy emission rate. that, show curves r_s-T_{cav} plane share similarities with G-T...

We examine cosmological inflation in a broad family of scalar-tensor models characterized by scalar-dependent non minimal kinetic couplings and Gauss-Bonnet terms. Using slow roll-approximation, we compute detail theoretical expectations observables as spectral indexes, scalar-to-tensor ratio, their running the terms parameters which characterize model. Hierarchies consistency equations relating scalar tensor pertubations higher order are presented examined at roll approximation for kind...