Gravitational collapse in generalized Vaidya space-time for Lovelock gravity theory

Abstract

In this work, we have assumed the generalized Vaidya solution in Lovelock theory of gravity in (n + 2)-dimensions. It has been shown that Gauss-Bonnet gravity, dimensionally continued Lovelock gravity and pure Lovelock gravity can be constructed by suitable choice of parameters. We have investigated the occurrence of singularities formed by the gravitational collapse in above three particular forms of Lovelock theory of gravity. The dependence of the nature of singularity on the existence of radial null geodesic for Vaidya space-time has been specially considered. In all the three models, we have shown that the nature of singularities (naked singularity or black hole) completely depend on the parameters. Choices of various parameters are shown in tabular form. In Gauss-Bonnet gravity theory, it can be concluded that the possibility of naked singularity increases with increase in dimensions. In dimensionally continued Lovelock gravity, the naked singularity is possible for odd dimensions for several values of parameters. In pure Lovelock gravity, only black hole forms due to the gravitational collapse for any values of parameters. It has been shown that when accretion is taking place on a collapsing object, it is highly unlikely to get a black hole. Finally on considering the phantom era in the expanding P. Rudra · U. Debnath ( ) universe it is observed that there is no possibility of formation of a black hole if we are in the Gauss-Bonnet gravity considering the accreting procedure upon a collapsing object.

Gravitational collapse in Vaidya space–time for Galileon gravity theory

“…Gravitational collapse has been extensively studied in modified gravity theory i.e., in Gauss-Bonnet, f (R) gravity, Lovelock theory etc [28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46]. Scheel [47] demonstrated that Openheimer-Snyder collapse in Brans-Dicke theory results in BHs rather than NSs with the positive values of brans-dicke parameter ω, they have speculated that the apparent horizon of a BH can pass outside the event horizon causing the decrease in the surface area over time.…”

“…The values of ω forces the BH, to radiate its scalar mass to infinity soon after the initial collapse. In [48] we get another relevant and interesting work regarding the gravitational collapse in the background of Brans-Dicke theory of gravity discussing the effects of different values of ω. Rudra et al in [49] has shown that lower the value of ω, greater is the chance of getting an NS.…”

“…As in [49] we will check that whether the nature of the end state of collapse can be regulated by any parameter of Galileon gravity. In this concern we must recall the fact that in [44] while working with Lovelock gravity, we saw that greater the deviation from Einstein gravity greater was the tendency to have the NS. So in this paper, we are mainly studying the nature of singularities (BH or NS) formed by the gravitational collapse in Galileon gravity and the conditions governing these.…”

Geometrothermodynamic analysis and P–V criticality of higher dimensional charged Gauss–Bonnet black holes with first order entropy correction

“…We have seen that higher dimensional background increases the possibilities to have a naked singularity rather than a BH spacetime wrapped by an event horizon [67,68]. That is, the BHs are less stable in higher dimensions.…”

Conformal symmetries in generalised Vaidya spacetimes

“…Detailed study of continual gravitational collapse of these spacetimes in the context of the Cosmic Censorship Conjecture were done in [22,23]. In the geometrical context, gravitational collapse has been considered in Lovelock gravity theory [24], black holes in dynamical cosmology backgrounds [25] and in electromagnetic fluids [26]. The influence of dust, radiation, quintessence and the cosmological constant are included in these studies.…”