Browsing by Author "Deshkar, D. W."

Now showing 1 - 6 of 6

Exact non-spherical radiating collapse
(2006-07-30) Ghosh, S. G.; Deshkar, D. W.
We study the junction conditions for non-spherical collapsing radiating star consisting of a shearing fluid undergoing radial heat flow with outgoing radiation. Radiation of the system is described by plane symmetric version of Vaidya solution. Junction conditions which match the collapse solutions to an exterior Vaidya metric show that, at the boundary, the pressure is proportional to the magnitude of the heat flow vector. Physical quantities, analogous to spherical symmetry related to the local conservation of momentum and surface red-shift, are also obtained. Finally, exact gravitational collapse solutions, for both shear and shear-free case, have been obtained by integrating a field equation.
Five dimensional dust collaspe with cosmological constant
(2006-07-31) Ghosh, S. G.; Deshkar, D. W.; Saste, N. N.
We study ﬁve dimensional spherical collapse of a inhomogeneous dust in presence of a positive cosmological constant. The general interior solutions, in the closed form, of the Einstein ﬁeld equations, i.e., the 5D Tolman-Bondi-de Sitter, is obtained which in turn is matched to exterior 5D Scwarschild-de Sitter. It turns out that the collapse proceed in the same way as in the Minkowski background, i.e., the strong curvature naked singularities form and thus violate the cosmic censorship conjecture. A brief discussion on the causal structure singularities and horizons is also given.
Gravitational collapse of perfect fluid in self-similar higher dimensional space-times
(2011-07-05) Ghosh, S. G.; Deshkar, D. W.
We investigate the occurrence and nature of naked singularities in the gravitational collapse of an adiabatic perfect ﬂuid in self-similar higher dimensional space-times. It is shown that strong curvature naked singularities could occur if the weak energy condition holds. Its implication for cosmic censorship conjecture is discussed. Known results of analogous studies in four dimensions can be recovered.
Higher dimensional dust collapse with a cosmological constant
(2005-07-01) Ghosh, S. G.; Deshkar, D. W.
The general solution of the Einstein equation for higher dimensional (HD) spherically symmetric collapse of inhomogeneous dust in presence of a cosmological term, i.e., exact interior solutions of the Einstein ﬁeld equations is presented for the HD Tolman-Bondi metrics imbedded in a de Sitter background. The solution is then matched to exterior HD Scwarschild-de Sitter. A brief discussion on the causal structure singularities and horizons is provided. It turns out that the collapse proceed in the same way as in the Minkowski background, i.e., the strong curvature naked singularities form and that the higher dimensions seem to favor black holes rather than naked singularities.
Non-spherical collapse of a radiating star
(2002-04-01) Ghosh, S. G.; Deshkar, D. W.
We study the junction conditions for non-spherical (plane symmetric) collapsing ra- diating star consisting of a shearing ﬂuid undergoing radial heat ﬂow with outgoing radiation. Radiation of the system is described by plane symmetric Vaidya solution. Physical quantities relating to the local conservation of momentum and surface red-shift are also obtained.
Role of the space-time dimensions & the fluid equation of state in spherical gravitational collapse
(2011-07-06) Dadhich, Naresh; Ghosh, S. G.; Deshkar, D. W.
We study the spherically symmetric collapse of a ﬂuid with non-vanishing radial pressure in higher dimensional space-time. We obtain the general exact solution in the closed form for the equation of state (Pr = γρ) which leads to the explicit construction of the root equation governing the nature (black hole versus naked singularity) of the central singularity. A remarkable feature of the root equation is its invariance for the three cases: (D + 1, γ = −1), (D, γ = 0) and (D − 1, γ = 1) where D is the dimension of space-time. That is, for the ultimate end result of the collapse, D-dimensional dust, D + 1 - AdS (anti de Sitter)-like and D − 1 - dS-like are absolutely equivalent.