arXiv subjects

Jay Verma Trivedi

Publications and source records attributed to Jay Verma Trivedi.

3 recordsLinked to original sources

arXiv2026

Generalized JMN Naked Singularity Models

We construct a generalized class of Joshi-Malafarina-Narayan (JMN) naked singularity spacetimes that arise as equilibrium end states of gravitational collapse with non-vanishing tangential pressure. The generalization introduces density inhomogeneity through a radially dependent mass function $F(r)=(M_0+M_n r^n)r^3$, leading to a two-parameter family of solutions matched smoothly to an exterior Schwarzschild spacetime. The observational properties of the spacetime are then examined through shadow formation and thin accretion disk emission. We find that when the photon sphere lies in the exterior Schwarzschild region, the shadow is identical to that of a Schwarzschild black hole. Accretion disk spectra show enhanced high-frequency emission compared to Schwarzschild, while deviations from the original JMN model remain small due to strong constraints on the inhomogeneity parameter. These results indicate that the generalized model effectively serves as a small perturbation of the JMN spacetime, demonstrating the robustness of JMN-type naked-singularity geometries.

gr-qc↗

arXiv2026

Astrophysical Black holes: An Explanation for the Galaxy Quenching

In light of increasing observational evidence supporting the existence of ultra-compact objects, we adopt the term astrophysical black hole to refer to any object having a huge mass confined within a sufficiently small region of spacetime. This terminology encompasses both the classical black hole solutions predicted by general relativity, as well as alternative compact objects that may not possess an event horizon. We propose models of Astrophysical Black holes (ABHs) without event horizons (EHs), as a more viable explanation for the long-term quenching phenomenon in galaxies. At the same time, the short-term quenching is explained here in terms of an efficient feedback expected in the models of stellar-mass astrophysical black holes (StMABHs). We have calculated the radiative flux from the disk in a general spherically symmetric metric background and used it to contrast the distinctive features of the BHs and ABHs scenarios. We demonstrate the relative ease of wind generation from the accretion disk surrounding an ABH without an event horizon, compared to a BH, and highlight the significant strength of these winds. The nature of the feedbacks arising from accretion onto a BH and an ABH in the `quasar' and `radio' modes are compared and some possible observational signatures of the StMABHs are pointed out.

gr-qc↗

arXiv2023

Gravitational collapse of scalar and vector fields

We study here the unhindered gravitational collapse of spatially homogeneous (SH) scalar fields $ϕ$ with a potential $V_{s}(ϕ)$, as well as vector fields $\tilde{A}$ with a potential $V_{v}(B)$ where $B=g(\tilde{A},\tilde{A})$ and $g$ is the metric tensor. We show that in both cases, classes of potentials exist that give rise to black holes or naked singularities depending on the choice of the potential. The strength of the naked singularity is examined, and they are seen to be strong, in the sense of Tipler, for a wide class of respective potentials. We match the collapsing scalar/vector field with a generalized Vaidya spacetime outside. We highlight that full generality is maintained within the domain of SH scalar or vector field collapse.

gr-qc↗