Ju n 20 04 High-and low-frequency quasi-periodic oscillations in the X-ray light curves of the black hole transient H 1743 – 332

We present a variability study of the black hole candidate and X-ray transient H1743–332 during its 2003/2004 outburst. We analyzed five Rossi X-ray Timing Explorer observations that were performed as part of a multi-wavelength campaign, as well as six observations from the early rise of the outburst. The source was observed in several black hole states and showed various types of X-ray variability, including high frequency quasi-periodic oscillations (QPOs) at 240 Hz and 160 Hz (i.e. with a 3:2 frequency ratio), several types of low frequency QPOs, and strong variations on a time scale of a few hundred seconds. The discovery of high frequency QPOs in H1743–332 supports predictions that these QPOs should be more easily observed in high inclination systems. In one of our observations we observed a transition in count rate and color, during which we were able to follow the smooth evolution of the low-frequency QPOs from type-B to type-A. We classify the X-ray observations and QPOs, and briefly discuss the QPOs in terms of recently proposed models. Subject headings: stars: individual (H1743–332) — stars: oscillations —X-rays: binaries — X-rays: stars