Discovery of 69 ms periodic X-ray pulsations in A0538 — 66
Discovery of 69 ms periodic X-ray pulsations in A0538 — 66
复制标题
在 A0538 — 66 中发现 69 毫秒周期性 X 射线脉动
作者：
G. Skinner;D. Bedford;R. Elsner;D. Leahy;M. Weisskopf;J. Grindlay
周期性的X射线瞬变A0538-66和它的光学对应物都以16.6天的倍数1 -3的间隔经历爆发。爆发的时间受到明显的抖动，虽然通常很短（<1天），但事件有时会持续近一个完整的周期4。该系统位于大麦哲伦云（LMC）的方向上，静止态光学吸收线的多普勒频移表明它是LMC的成员5，6。这意味着爆发时的X射线光度为8× 1038 ergs −1（2-17 keV）1，比任何其他恒星X射线源都要高。我们在这里报告的检测，在观测期间与爱因斯坦天文台在爆发时，X射线脉冲与周期为69.2126毫秒从A0538-66，增加了这个系统的独特属性，是最快的X射线脉冲星已知的是在一个二元系统。观测到的周期变化率表明，该源是一个偏心双星系统，其中两个组成部分在爆发期间彼此接近，甚至可能浸入一个共同的包络线中。
Both the recurrent X-ray transient A0538–66 and its optical counterpart undergo outbursts at intervals which are multiples of 16.6 days1–3. The times of outbursts are subject to appreciable jitter and although typically brief (<1 day) the event can, on occasions, last nearly a complete cycle4. The system lies in the direction of the Large Magellanic Cloud (LMC) and the Doppler shifts of the quiescent-state optical absorption lines indicate that it is a member of the LMC5,6. This implies an X-ray luminosity during outburst of 8×1038ergs s−1 (2–17 keV)1—higher than that of any other ‘stellar’ X-ray source. We report here the detection, during observations with the Einstein Observatory at the time of an outburst, of X-ray pulsations with a period of 69.2126 ms from A0538–66, adding to the unique properties of this system that of being the fastest X-ray pulsar known to be in a binary system. The observed rate of change of period shows the source to be an eccentric binary system in which the two components approach close to each other during the outbursts and may even become immersed in a common envelope.