XPNAV-1和NICER对Crab脉冲星观测数据的比较分析

Comparison and analysis of Crab pulsar observation data from XPNAV-1 and NICER

通过对比NICER(Neutron Star Interior Composition Explorer)和XPNAV-1(X-ray Pulsar Navigation-1)关于Crab脉冲星同一时段(108天)观测数据的计时处理结果,发现在周期跃变发生前的时段(95天),NICER数据的拟合前计时残差的RMS(root mean square)为5.77μs,远优于XPNAV-1数据的拟合前计时残差的RMS 51.56μs,体现了NICER在有效面积、探测效率、数据采集等方面的优势,给未来我国的X射线脉冲星探测器研制提供了发展方向;而在周期跃变发生后的时段(13天),发现XPNAV-1数据的拟合前计时残差的RMS为55.87μs,而NICER数据的拟合前计时残差的RMS为167.27μs,周期跃变对NICER的影响更大,说明在处理周期跃变发生后时段的NICER数据时,由于NICER的观测精度非常高,需要更频繁地更新Crab星历。最后分别得到了两个探测器整段数据的计时残差。XPNAV-1数据的拟合前计时残差的RMS为55.94μs,而NICER数据的拟合前计时残差的RMS为64.34μs,这说明NICER数据受周期跃变影响更为明显,进一步证明了上述结论。

By comparing the timing processing results of the observation data of Crab pulsar in the same period(108 days)from NICER and XPNAV-1,it is found that in the period before glitch(95 days),the RMS=5.77μs of the pre-fit timing residuals of NICER data is much better than the RMS=51.56μs of pre-fit timing residuals of XPNAV-1 data.It reflects the advantages of NICER detector in effective area,detection efficiency,data acquisition and other aspects,and provides the development direction for X-ray pulsar detectors in China in the future;In the period after glitch(13 days),it is found that the RMS of pre-fit timing residuals of XPNAV-1 data is 55.87μs.The RMS of the pre-fit timing residuals of NICER data is 167.27μs.glitch has a larger impact on NICER,which means that when processing NICER data in the period after glitch,due to the very high observation precision of NICER,it is necessary to update the Crab ephemeris more frequently.At last,the timing residuals of the whole data of the two detectors are obtained.The RMS of the pre-fit timing residuals of XPNAV-1 data is 55.94μs,and the RMS of the pre-fit timing residuals of NICER data is 64.34μs,which further demonstrates the above conclusions.