ASCA observations of OAO 1657−415 and its dust-scattered X-ray halo
ASCA observations of OAO 1657−415 and its dust-scattered X-ray halo
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DOI：
10.1111/j.1365-2966.2006.10003.x
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发表时间：
2000-12
影响因子：
4.8
通讯作者：
M. D. Audley;F. Nagase;K. Mitsuda;L. Angelini;R. Kelley
中科院分区：
文献类型：
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作者：
M. D. Audley;F. Nagase;K. Mitsuda;L. Angelini;R. Kelley
我们报告了 ASCA 对高质量 X 射线双星脉冲星 OAO 1657-415 的两次观测。日食中期附近的一次短暂观测发现光源处于低强度状态，具有弱连续谱和以 6.4 keV 荧光线为主的铁发射。后来的一次更长时间的观测发现源头处于高强度状态，并覆盖了日食中的未食部分。在高强度状态下，由于脉冲星附近的物质散射，非食光谱具有吸收的连续谱成分，并且 80% 的荧光铁发射来自距脉冲星不到 19 光秒的距离。我们发现了一个散布着灰尘的 X 射线晕，其强度在日食期间衰减。我们使用这个光环来估计到源的距离为 7.1 ± 1.3 kpc。
We report on two ASCA observations of the high-mass X-ray binary pulsar OAO 1657-415. A short observation near mid-eclipse caught the source in a low-intensity state, with a weak continuum and iron emission dominated by the 6.4-keV fluorescent line. A later, longer observation found the source in a high-intensity state and covered the uneclipsed through mid-eclipse phases. In the high-intensity state, the non-eclipse spectrum has an absorbed continuum component due to scattering by material near the pulsar and 80 per cent of the fluorescent iron emission comes from less than 19 light-second away from the pulsar. We find a dust-scattered X-ray halo whose intensity decays through the eclipse. We use this halo to estimate the distance to the source as 7.1 ± 1.3 kpc.