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Paper: DNOs and QPOs in Cataclysmic Variables
Volume: 330, The Astrophysics of Cataclysmic Variables and Related Objects
Page: 227
Authors: Warner, B.; Woudt, P.A.
Abstract: We describe some of the recent observations of Dwarf Nova Oscillations and Quasi-Periodic Oscillations in cataclysmic variable stars. The similarities to high frequency QPOs seen in X-Ray binaries make this an increasingly useful field to explore. Our principal new result is the discovery of 1:2:3 harmonic structure in the DNOs of VW Hyi late in outburst. Similar structure is seen in the QPOs of some black hole and neutron star X-Ray binaries. In VW Hyi there is a sudden frequency-doubling when the DNO period reaches ~ 39 s. This first harmonic increases in period to ~ 28 s at which point the second harmonic appears. Both harmonics continue with increasing period, together or separately, with an occasional appearance of the fundamental, until the latter reaches ~ 105 s, by which time VW Hyi has fallen to its quiescent magnitude. We also report the first extensive observations of DNOs in a dwarf nova (OY Car) in quiescence. These are lpDNOs (longer period DNOs) and show similar short time scale properties to the DNOs and lpDNOs seen in outburst.
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