标题： 射电辐射中的轨道调制和更长期的变异来自天鹅座X-1 显示英文标题

标题： Orbital modulation and longer-term variability in the radio emission from Cygnus X-1

摘要： 20个月对天鹅座X-1在15 GHz射电辐射的观测，始于1996年10月，显示在5.6天的双星周期内有变化，但相位与X射线波长的变化存在偏移。 还有时间尺度为150天的长期变化，这些变化与软X射线通量的关系较为松散。 在整个期间，该源都处于硬/低X射线状态。 平均15-GHz通量密度为13 mJy，射电谱是平坦的，轨道调制的半振幅约为2 mJy。 我们讨论了调制的可能起源及其与软X射线发射的关系。 显示英文摘要

摘要： 20 months of observations of the radio emission at 15 GHz from Cygnus X-1, starting in 1996 October, show variations at the binary period of 5.6 days, but with a phase offset from those at X-ray wavelengths. There are also longer-term variations on a time-scale of 150 days which are only loosely related to the soft X-ray flux. The source was in the hard/low X-ray state throughout this period. The mean 15-GHz flux density is 13 mJy, the radio spectrum is flat, and the semi-amplitude of the orbital modulation about 2 mJy. We discuss the possible origins of the modulation and the relationship to the soft X-ray emission.