  By detecting high frequency quasi-periodic oscillations (QPOs) and estimating
frequencies of them during the decaying tail of giant flares from Soft
Gamma-ray Repeaters (SGRs) useful constraints for the equation of state (EoS)
of superdense matter may be obtained via comparison with theoretical
predictions of eigenfrequencies. We used the data collected by the Rossi X-Ray
Timing Explorer (RXTE/XTE) Proportional Counter Array (PCA) of a giant flare of
SGR 1806-20 on 2004 Dec 27 and applied a Bayesian periodicity detection method
(Gregory & Loredo, 1992) for the search of oscillations of transient nature. In
addition to the already detected frequencies, we found a few new frequencies
(f_{QPOs} ~ 16.9, 21.4, 36.4, 59.0, 116.3 Hz) of oscillations predicted by
Colaiuda et al. (2009) based on the APR_{14} EoS (Akmal et al., 1998) for SGR
1806-20.
