Synoptic Study of an X-Ray Nova in Outburst (ADP 2000)
In the completed work listed above, we present an X--ray spectral and timing analysis of 4131543-47 during its 2002 outburst based on 49 pointed observations obtained using the Rossi X-ray Timing Explorer (RXTE). The outburst reached a peak intensity of 4.2 Crab in the 2-12 keV band and declined by a factor of 32 throughout the month-long observation. A 21.9+/-0.6 mJy radio flare was detected at 1026.75 MHz two days before the X-ray maximum; the radio source was also detected late in the outburst, after the X-ray source entered the hard state. The X-ray light curve exhibits the classic shape of a rapid rise and an exponential decay. The spectrum is soft and dominated by emission from the accretion disk. The continuum is fit with a multicolor disk blackbody (kT-max = 1.04 keV) and a power-law (Gamma -2.7). Midway through the decay phase, a strong low-frequency quasi-periodic oscillation (QPO; nu = 7.3-8.1 Hz) was present for several days. The spectra feature a broad Fe K line that is asymmetric, suggesting that the line is due to relativistic broadening rather than Gomptonization. Relativistic Laor models provide much better fits to the line than non-relativistic Gaussian models, particularly near the beginning and end of our observations. The line fits yield estimates for the inner disk radius that are within 6 GM/c 2; this result and additional evidence indicates that this black hole may have a non-zero angular momentum. In current work, we are in the process of analyzing a huge set of RXTE data (-100 pointed observations) for H1743-322, which was in eruption throughout most of 2003. The source s behavior is remarkable. It displays all of the canonical X-ray states, sometimes in unusual ways. In this short report, we feature a single important result, namely, the detection of a pair of high-frequency QPOs. The bright flaring behavior is of special interest. During the flares the shape of the power spectrum and the presence of low-frequency QPOs indicate that the source is in the steep power-law (SPL or very high) state. It is in this state that the high-frequency QPOs, which are believed to emanate from the very inner accretion disk, were oberved. Specifically, we observe a 240 Hz QPO at a significance of 4.7sigma and a 162 Hz QPO at 3.7sigma. The higher frequency QPO was discovered by Homan et al. in an independent data set; they also found marginal evidence (2.5sigma)