LOW-FREQUENCY QUASI-PERIODIC OSCILLATIONS IN THE X-RAY TRANSIENT GRO J1719-24

We present the results of an analysis of the time variability of the s oft X-ray transient GRO J1719-24 (Nova Oph 1993) as observed with BATS E. Our analysis covers the entire similar to 80 day outburst, beginnin g with the first detection on September 25, 1993. We obtained power de nsity spectra (PDS) of the data in the 20-100 keV energy band covering the frequency interval 0.002-0.488 Hz. The PDS show a significant qua si-periodic oscillations (QPO) peak whose centroid frequency increased from similar to 0.04 Hz at the onset of the outburst, to similar to 0 .3 Hz at the end. Additional noise is present in the PDS which we desc ribe in terms of two components. We find that the evolution of the PDS can be described as a gradual stretching by a factor similar to 7.5 i n frequency of the power spectrum.