In this article, we conduct a sequential study of possible observable images of black hole
simulators described by two recently obtained rotating geometries in Einstein gravity …

We study spherically symmetric configurations of the quadratic f (R) gravity [f (R)= RR 2/6 μ
2]. In the case of a purely gravitational system, we have fully investigated the global …

Extended metric-Palatini gravity, quadratic in the antisymmetric part of the affine curvature, is
known to lead to the general relativity plus a geometric Proca field. The geometric Proca …

Abstract The Event Horizon Telescope has recently observed the images and shadows of
the compact objects M87* and Sgr A* at the centres of the galaxies Messier 87 and Milky …

We study linear perturbations against static spherically symmetric background
configurations of general relativity with a real scalar field (SF), which is minimally coupled …

The recent advancements in black hole imaging have opened a new era of probing horizon-
scale physics with electromagnetic radiation. However, a feature of the observed images, a …

Recently, it has been reported that photons can traverse naked singularities in the Janis-
Newman-Winicour and Born-Infeld spacetimes when these singularities are appropriately …

Listening to echoes has long been a way to estimate distances, a technique whose
backbone is the time delay. The gravitational field also creates a time delay, called Shapiro …

This paper investigates observable signatures of hot spots orbiting Reissner-Nordström
(RN) black holes and naked singularities. For an RN black hole, we find two discernible …