High-Energy Spectral and Temporal Characteristics of GRO J1008–57
High-Energy Spectral and Temporal Characteristics of GRO J1008–57
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DOI：
10.1086/306785
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发表时间：
1999-02
期刊：
影响因子：
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通讯作者：
C. Shrader;F. Sutaria;K. P. Singh;D. Macomb
中科院分区：
文献类型：
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作者：
C. Shrader;F. Sutaria;K. P. Singh;D. Macomb
GRO J1008-57是1993年7月在康普顿伽马射线天文台（CGRO）的爆发和瞬态源实验（BATSE）中发现的一个瞬态X射线源。它在20-60 keV的能量带中达到了最大强度，约为蟹状星云的1.4倍。在93.5秒的周期内检测到X射线强度的脉动。它后来被确定为Be星星的X射线瞬变子类的成员。除了BATSE，GRO J1008-57在爆发期间还被几个高能实验观测到：ROSAT，ASCA和CGRO/OSSE。这些非同时但同时的观测发生在爆发光曲线峰值附近和之后不久。我们报告的CGRO和ASCA数据集的综合分析的第一次。我们试图模拟宽带高能连续谱分布和相位分辨谱。宽带，相位平均连续很好地近似的指数截止的幂律。根据我们的光谱分析，6.4 keV线发射由于铁的证据。的脉冲轮廓的能量依赖性进行检查，以确定在该能量的低能量的双峰轮廓检测到的ASCA演变成单峰脉冲轮廓检测到的BATSE。我们讨论的磁场和光束分布的GRO J1008-57的脉冲轮廓的影响。对BATSE和罗西X射线定时探测器/ASM通量历史的分析表明，P约为135天。我们进一步建议，一个短暂的磁盘很可能形成在发作的爆发。
A transient X-ray source, GRO J1008-57, was discovered by the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory (CGRO) in 1993 July. It reached a maximum intensity of about 1.4 times that of the Crab, in the 20-60 keV energy band. Pulsations in the X-ray intensity were detected at a period of 93.5 s. It has subsequently been determined to be a member of the Be star subclass of X-ray transients. In addition to BATSE, GRO J1008-57 was observed during its outburst by several pointed high-energy experiments: ROSAT, ASCA, and CGRO/OSSE. These nonsimultaneous but contemporaneous observations took place near and shortly after the peak of the outburst light curve. We report for the first time on a combined analysis of the CGRO and ASCA data sets. We have attempted to model the broadband high-energy continuum distribution and phase-resolved spectra. The broadband, phase-averaged continuum is well approximated by a power law with an exponential cutoff. Evidence for 6.4 keV line emission due to Fe is presented based on our spectral analysis. The energy dependence of the pulse profiles is examined in order to determine the energy at which the low-energy double-peaked profile detected by ASCA evolves into single-peaked pulse profile detected by BATSE. We discuss the implications of this pulse profile for the magnetic field and beam distribution for GRO J1008-57. Analysis of the BATSE and Rossi X-Ray Timing Explorer/ASM flux histories suggests that P~135 days. We further suggest that a transient disk is likely to form during episodes of outbursts.