Swift BAT and RXTE Observations of the Peculiar X-Ray Binary 4U 2206+54: Disappearance of the 9.6 Day Modulation
Swift BAT and RXTE Observations of the Peculiar X-Ray Binary 4U 2206+54: Disappearance of the 9.6 Day Modulation
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DOI：
10.1086/509319
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
R. Corbet;C. Markwardt;J. Tueller
中科院分区：
文献类型：
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作者：
R. Corbet;C. Markwardt;J. Tueller
快速爆发预警望远镜（BAT）对高质量x射线双星4U 2206+54的观测没有显示出先前报道的由罗西x射线计时探测器（RXTE）全天监测器（ASM）观测到的9.6天的调制。相反，BAT光曲线功率谱的最强峰出现在19.25±0.08天的周期，是RXTE ASM周期的两倍。与折叠的ASM光曲线的最大值相比，折叠的BAT光曲线的最大值也延迟了。最近的ASM数据在9.6天的周期内折叠两次，显示出与折叠的BAT光曲线相似的形态。这表明明显的周期加倍是近期的长期变化，而不是能源依赖效应。因此，9.6天的周期并不是光曲线的一个永久的强烈特征。我们认为4U 2206+54的轨道周期可能是先前提出值的两倍。
Observations of the high-mass X-ray binary 4U 2206+54 with the Swift Burst Alert Telescope (BAT) do not show modulation at the previously reported period of 9.6 days found from observations made with the Rossi X-Ray Timing Explorer (RXTE) All-Sky Monitor (ASM). Instead, the strongest peak in the power spectrum of the BAT light curve occurs at a period of 19.25 ± 0.08 days, twice the period found with the RXTE ASM. The maximum of the folded BAT light curve is also delayed compared to the maximum of the folded ASM light curve. The most recent ASM data folded on twice the 9.6 day period show similar morphology to the folded BAT light curve. This suggests that the apparent period doubling is a recent secular change rather than an energy-dependent effect. The 9.6 day period is thus not a permanent strong feature of the light curve. We suggest that the orbital period of 4U 2206+54 may be twice the previously proposed value.