Her X-1 35天开关周期是由于中子星的自由进动产生的吗?(英文)

Is the 35 Day Cycle of Her X-1 Caused by the Free Precession of the Neutron Star?

一些作者提出Her X-1的35天开关周期是由中子星的自由进动引起的。对这个模型我们进行了理论计算,并将理论结果和观测资料进行了比较,我们发现: (1)Hcr X-1的35天周期的光变曲线的理论值与观测(Jones ＆ Forman,1976)不符。 (2)在这个模型中脉冲宽度和强度随35天周期有很大的变化(见图4和图5),也与观测不符(如Gruber等人1980年的观测)。 (3)Parmar等人(1985)报道他们没有发现预期的Her X-1的X射线辐射35天周期的变化,这也同中子星自由进动的模型不一致。 Pravdo等(1977)建议观测到的X射线脉冲是由产生于中子星表面附近的、对称的辐射束经汤姆逊散射而形成。我们用强磁场中的汤姆逊散射理论所作的分析表明,该模型可以较好地与观测相符。

Some authors suggested that the 35 day clock mechanism of Her X-1 is caused by the presession of the neutron star. We performed calculations for such a model. The theoretical results are compared with observations. We find:(1) The theoretical light curve of Her X-l covering the entire 35 day cycle is not in agreement with that given by Jones and Forman (1976).(2) The change of pulse width and intensity in the model with 35 day phase is large, which seems to be not in agreement with observations(for example, the observation by Gruber et al. 1980).(3) Parmar et al. (1985) reported that they did not see the expected 35 day variation in X-ray intensity, this is not in agreement with the model either.Pravdo et al. (1977) suggested a model of Thomson scattering. In our analysis we also used this assumption. It can be shown that in different energy of X-rays the relationship between the pulse profiles and the 35 day phases is different, as it was shown in the observations by Trumper et al. (1986).