Quasi-p erio dic oscillations in quasars to nano-quasars
Sandip K. Chakrabart1,2*
1 S.N. Bose National Center for Basic Sciences, JD-Block, Salt Lake, Kolkata 700 098, Inda
2 Centre for Space Physics, Chalantika 43, Garia Station Rd., Kolkata 700 084, India

Abstract. TAUVEX brings us a unique opportunity to explore the temporal variability of UV emitting ob jects in the sky. One of the questions that we intend to resolve with TAUVEX is whether the `variabilities' detected in active galaxies and quasars and in radiations around massive black holes in general are just random variations of the intensities or these are intrinsic to the disk system, and possibly due to the quasi-periodic oscillations (QPOs) which are well known to be observed in smaller black holes (nano-quasars). In this article, we present a physical mechanism for the QPOs and show that this is a generic mechanism which should be manifested in all types of active compact ob jects, ranging from quasars to nano-quasars. We propose some tests by which we may be able to tell if these are QPOs, even without waiting for a large number of cycles to test the periodicity. We present a few examples to impress that perhaps we have already seen QPOs in some ob jects. Multi-wavelength observation capabilities in TAUVEX may be used to pinpoint the nature of the variable sources more accurately.

Keywords: Black hole physics - radiative transfer - shock waves - X-rays: binaries

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