Research Papers (JVN)
Permanent URI for this collectionhttp://localhost:4000/handle/11007/400
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Item Nucleosynthesis in bouncing cosmologies(Kluwer Academic Publishers, 1982-05-06) Narlikar, J. V.; Apparao, K. M. V.It is shown that certain anomalies connected with the primordial abundances of light nuclei may be resolved if it is assumed that the Universe oscillates between phases of finite densities. Since general relativity does not produce bouncing models of the Universe, such models are obtained through the introduction of a negative energy scalar field of zero rest mass. It is shown that all the relevant parameters of the dynamics of the model and the nucleosynthesis in it are determined by observations and that a self-consistent picture emerges. The model is capable of admitting more than three neutrino flavours without an embarrassingly high primordial helium content. It is also shown that the calculations could be adapted to described production of light nuclei in compact massive bouncing objects.Item White holes and high energy astrophysics(Kluwer Academic Publishers, 1975-01-01) Narlikar, J. V.; Apparao, K. M. V.The role of exploding objects in high-energy astrophysics is discussed. Quantitative results are obtained for the simple case of the canonical white hole which explodes from a singularity and consists of pressure-free matter in the comoving frame of reference. General relativity is used for calculating the dynamical results. Applications to X-ray background, transient X-ray sources, gamma-ray bursts, and high energy cosmic rays are considered. White holes of more general types are discussed in a qualitative manner.