2003 (IPP)
Permanent URI for this collectionhttp://localhost:4000/handle/11007/626
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Item Origin and interpretation of kilohertz QPOs from strange stars in X-ray Binary system: Theoretical hydrodynamical description(2011-07-05) Mukhopadhyay, B.; Ray, Subharthi; Dey, Jishnu; et al.We model and interpret the Kilohertz QPOs from the hydrodynamical description of accretion disk around a rapidly rotating compact strange star. The higher QPO frequency is described by the viscous effects of accretion disk leading to shocks, while the lower one is taken to be the Keplerian motion of the accreting matter. Comparing our results with the observations for two of the fastest rotating compact stellar candidates namely, 4U 1636−53 and KS 1731−260, we find that they match to a very good approximation, thus interpreting them as strange stars.Item Possible evidence of surface vibration of realistic strange stars from stellar observations(2011-07-05) Ray, Subharthi; Dey, Jishnu; Dey, Mira; et al.Emission lines in the eV and keV range by certain stellar candidates from their recent analysis invoke the question of their possible origin. These stars under consideration, are the 4U 0614+091 (0.65, 0.86, and 1.31 keV ), 2S 0918−549 (0.8 keV with width 55 eV ), 4U 1543−624 (0.7 keV ), 4U 1850 −087 (0.7 keV ) and 4U 1820−30 (0.6 and 0.9 keV ) and also the 0.6 keV excess emission in RX J170930.2−263927. Recently, it has been suggested that the resonance absorption at ∼ in 0.7, 1.4, 2.1 and 2.8 keV 1E1207−5209 and 0.35, 0.7 and 1.4 keV RX J1856.5−3754 are due to harmonic surface vibrations in strange stars. We propose that these harmonic vibrations may also responsible for emission lines in the above mentioned compact stellar candidates.