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Research Accomplished

For the first time in the literature, we establish that transonic Transonic accretion onto astrophysical black holes is a very interesting example of classical analogue system found naturally in the Universe. An accreting black hole system as a classical analogue is unique in the sense that only for such a system, both kind of horizons, the electromagnetic and the acoustic (generated due to transonicity of accreting fluid) are simultaneously present in the same system. Hence accreting astrophysical black holes are the most ideal candidate to study theoretically and to compare the properties of these two different kind of horizons. Such a system is also unique in the aspect that accretion onto the black holes represents the only classical analogue system found in the nature so far, where the analogue Hawking temperature may exceed the actual Hawking temperature. We also show that acoustic white holes can also be generated if the accretion flow is multi-transonic and if such multi-transonic black-hole accretion encounters a stable shock. Such a white hole, produced at the shock, is always flanked by two acoustic black holes generated at the inner and the outer sonic points.

Our formalism proves that in general the transonic accretion in astrophysics can be considered as an example of the classical analogue gravity model.
next up previous
Next: Ongoing Work/Future Project Up: Analogue Gravity Phenomena: Hawking Previous: Introduction
Tapas Kumar Das 2009-01-17