IUCAA Preprints
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Item A duality relation for fluid spacetime(2015-03-11) Dadhich, Naresh; Patel, L.K.; Tikekar, R.Item Domain walls in kaluza-klein spacetime(2015-03-01) Patel, L.K.; Dadhich, Naresh; Tikekar, R.Three families of exact solutions of Einstein field equations are found. Each family contains three parameters. Two of these families represent thick domain walls in a five dimensional Kaluza-Klein spacetime.The dynamical behaviour of our models is briefly discussed. The spacetime in all the cases is found to be reflection symmetric with respect to the wall.Item Higher dimensional analogue of McVittie solution(2015-03-01) Patel, L.K.; Tikekar, R.; Dadhich, NareshItem Global monopole as dual-vacuum solution in kaluza-klein spacetime(2015-03-01) Dadhich, Naresh; Patel, L.K.; Tikekar, R.By application of the duality transformation, which implies interchange of active and passive electric parts of the Riemann curvature (equivalent to interchange of Ricci and Einstein tensors) it is shown that the global monopole solution in the Kaluza-Klein spacetime is dual to the corresponding vacuum solution. Further we also obtain solution dual to flat space which would in general describe a massive global monopole in 4-dimensional Euclidean space and would have massless limit analogus to the 4-dimensional dual-flat solution.Item A class of cylindrically symmetric models in string cosmology(2015-02-09) Tikekar, R.; Patel, L.K.; Dadhich, NareshA new class of physically relevant explicit solutions for string cosmological models endowed with cylindrical symmetry on the background of singularity free cosmological space times have been obtained and their physical and the kinematical features are discussed. The matter free limits of this class of solutions are observed to be the singularity free vacuum solutions of Patel and Dadhich.Item Inhomogeneous cosmological models with heat flux(2015-02-07) Patel, L.K.; Tikekar, R.; Dadhich, NareshWe present a general class of inhomogeneous cosmological models filled with non-thermalized perfect fluid by assuming that the background spacetime admits two space-like commuting Killing vectors and has separable metric coefficients. The singularity structure of these models depends on the choice of the parameters and the metric functions, A number of previously known perfect fluid models follow as particular cases of this general class. Physical and geometrical features of these models are studied and the general expression for temperature distribution is givenItem On singularity free cosmological model(2015-01-13) Dadhich, Naresh; Tikekar, R.; Patel, L.K.Item Core-envelope model of compact stars(2011-07-06) Paul, B. C.; Tikekar, R.Item Relativistic superdense star models of pseudo spherodical space-time(2012-03-07) Tikekar, R.; Kanti, JotaniaThe physically viable models of compact stars like SAX (J1808.4-3658) can be obtained using Vaidya-Tikekar ansatz prescribing spheroidal geometry for their interior space-time. We discuss here the suitablitiy of an alternative ansatz in this context. The models of superdense star are proposed using a general three parameter family of solutions of relativistic field equations obtained adopting the altenative ansatz. The set up is shown to admitt physically viable models of superdense stars and strange matter stars such as Her. X-l.Item On relativistic models of strange stars(2006-01-01) Tikekar, R.; Jotania, KantiThe superdense stars with mass to size ratio greater than 0.3 are expected to be made up of strange matter. The ansatz prescrbing ge- ometry of a 3-paraboloid immersed in 4-dimensional Euclidean space for the 3-space of the interior spacetime of superdense star is shown to provide two parameter family of physically viable relativistic models of strange stars. The compact stellar con gurations with mass to size ratio greater than 0.3 are likely to admit only strange star interpretation.