Browsing by Author "Narasimha, D."
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Item 3C 273 : A gravitationally lensed quasar?(EDP Sciences, 1984-05-30) Chitre, S. M.; Narasimha, D.; Narlikar, J. V.; et al.It is suggested that the abnormal brightness of the quasar 3C 273, coupled with the observations of superluminal motions in its radio core B as well as the misalignment of its VLBI jet with the optical jet, can be understood by postulating a faint spheroidal lensing galaxy located about halfway along the line of sight to the quasar. The lens model also helps to understand why the quasar is found slightly off-centre with respect to its nebulosity. The probability for such a lens system to arise for 3C 273 by chance is shown to be no less than that computed on the basis of the relativistic beaming hypothesis. Further tests of the lens model are discussed.Item Constraints on the shape of the density spectrum from COBE and galaxy surveys(2014-11-23) Padmanabhan, T.; Narasimha, D.Item Constraints on the shape of the density spectrum from COBE and galaxy surveys(Wiley-Blackwell, 1992-10-28) Padmanabhan, T.; Narasimha, D.Item Doppler interpretation for close pairs and compact groups of quasars(American Astronomical Society, 1989-03-01) Narasimha, D.; Narlikar, J. V.We consider a Doppler model to account for (a) abnormal concentration of quasars in a given part of the sky and (b) the presence of two quasars with very nearly equal redshifts lying close to each other. The ejection parameters are explicitly determined and are shown to be reasonable for the nine quasars in the 1146+111 field. This example illustrates both (a) and (b). It is suggested that these calculations be carried out for quasars usually believed to be gravitationally lensed, as well as to other fields containing anomalously high concentration of quasars.Item Quasars Q 2345 + 007 A,B and 3C 273 : Gravitational Lenses?(Liege University Press, Liege, 1983-01-14) Narlikar, J. V.; Subramanian, Kandaswamy; Narasimha, D.; et al.