IUCAA Preprints
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Item sdfsdjinfdbfudhgu(2014-01-12)Item Classical essence of black hole radiation(2015-03-14) Nouri-Zonoz, M.; Padmanabhan, T.Item Nonlinear density evolution from an improved spherical collapse model(2015-03-14) Engineer, Sunu; Kanekar; Padmanabhan, T.Item Doing it with mirrors : Classical analogues for black hole radiation(2015-03-14) Srinivasan, K.; Padmanabhan, T.Item LRS bianchi-type I models with a time dependent cosmological “constant”(2015-03-14) Vishwakarma, R.G.; Abdussattar; Beesham, A.Plane symmetric homogeneous models of the universe with a perfect fluid distribution of matter and a variable cosmological "constant" representing the energy density of vacuum have been presented. The models are highly anisotropic in the early stages of evolution and ultimately evolve to the standard model at the present epoch. Of the three models obtained in this paper, one has an increasing vacuum energy density with time in the early universe. Though highly negative in the very early universe, the vacuum density soon becomes positive, and meets the observational limits at the present epoch. The negative vacuum in the early universe in this model, which decays numerically, adds up to anisotropy and at the same time contributes to the isotropization process. The second model is found to admit matter creation from the decaying vacuum energy whereas the third one, in which the vacuum density is always one third of the corresponding radiation density, is devoid of any such creation.Item Comments on ''remarks on a decrumpling model of the universe''(2015-03-14) Vishwakarma, R.G.A recent paper by Lima and Mohazzab has been examined and it is found that their results, that the Einstein field equations are consistent only for a dust and a turning point in the dynamics of the evolution is possible, are erroneous. This is due to their ignorance of the fact that the field equations and the energy conservation equation are not independent.Item Particle production and complex path analysis(2015-03-13) Srinivasan, K.; Padmanabhan, T.Item Evolution of multipolar magnetic field in isolated neutron stars(2015-03-13) Mitra, Dipanjan; Konar, Sushan; Bhattacharya, DipankarItem Two dimensional galaxy image decomposition(2015-03-13) Wadadekar, Yogesh; Robbason, Braxton; Kembhavi, A. K.Item Magnetic field evolution of accreting neutron stars - III(2015-03-13) Konar, Sushan; Bhattacharya, DipankarThe evolutionary scenario of the neutron star magnetic field is examined assuming a spindown-induced expulsion of magnetic flux originally confined to the core, in which case the expelled flux undergoes ohmic decay. The nature of field evolution, for accreting neutron stars, is investigated incorporating the crustal microphysics and material movement due to accretion. This scenario explains the observed field strengths of neutron stars but only if the crustal lattice contains a large amount of impurity which is in direct contrast to the models that assume an original crustal field.