标题： RXTE对微类星体GRO J1655-401996-97爆发的光谱观测 显示英文标题

标题： RXTE Spectral Observations of the 1996-97 Outburst of the Microquasar GRO J1655-40

摘要： RXTE提供了对GRO J1655-40 1996-97期间整个16个月爆发周期的全面覆盖。我们对这些数据进行了完整的光谱分析，包括2.5-20 keV范围内的52个PCA光谱和20 keV以上的HEXTE光谱。我们还包含了一个几乎连续的ASM光变曲线，每天有多个强度测量值。这些数据是在多色黑体盘/幂律模型的背景下进行解释的。该源处于非常高的、高/软和低/硬爆发状态。在非常高的状态下，该源在数小时到数天的时间尺度上表现出强烈的硬耀斑，这些耀斑与拟合的内吸积盘温度和半径的变化相关。在高/软状态下，光谱主要由吸积盘的软热辐射主导，光谱参数表明内盘半径和温度大约是恒定的。我们发现观测到的盘内半径与幂律成分的通量之间存在紧密关系。在强烈的硬耀斑期间，盘内半径在几天的时间尺度上最多减少了三倍。在耀斑期间观测到的盘内半径的明显减少可能是由于多色盘模型的失效，这由盘中径向温度分布的变陡以及光谱硬化增加所导致，而不是盘内半径的物理变化。假设我们的光谱模型在幂律发射较弱的时期有效，我们最可能的盘内半径值意味着a* < 0.7。这样的黑洞角动量低值与相对论框架拖拽和“盘震”模型作为RXTE某些观测中看到的300 Hz X射线QPO的解释不一致。 显示英文摘要

摘要： Excellent coverage of the entire 16-month 1996-97 outburst cycle of GRO J1655-40 was provided by RXTE. We present a full spectral analysis of these data, which includes 52 PCA spectra from 2.5-20 keV and HEXTE spectra above 20 keV. We also include a nearly continuous ASM light curve with several intensity measurements per day. The data are interpreted in the context of the multicolor blackbody disk/power-law model. The source is observed in the very high, high/soft, and low/hard outburst states. During the very high state, the source exhibits intense hard flares on time scales of hours to days which are correlated with changes in both the fitted temperature and radius of the inner accretion disk. During the high/soft state, the spectrum is dominated by the soft thermal emission from the accretion disk with spectral parameters that suggest approximately constant inner disk radius and temperature. We find that a tight relationship exists between the observed inner radius of the disk and the flux in the power-law component. During intense hard flares, the inner disk radius is observed to decrease by as much as a factor of three on a time scale of days. The apparent decrease of the inner disk radius observed during the flares may be due to the failure of the multicolor disk model caused by a steepening of the radial temperature profile in the disk coupled with increased spectral hardening and not physical changes of the inner disk radius. Assuming that our spectral model is valid during periods of weak power-law emission, our most likely value for the inner disk radius implies a* < 0.7. Such a low value for the black hole angular momentum is inconsistent with the relativistic frame dragging and the `diskoseismic' models as interpretations for the 300 Hz X-ray QPO seen during some of these RXTE observations.