摘要
讨论了X射线脉冲星光子到达的周期平稳Poisson模型和到达时刻(Time of arrival,TOA)估计问题.在此基础上,得到了脉冲到达时刻的最大似然估计和克拉美-罗限(Cramer-Rao boundary,CRB),并推导了低信噪比情况下的似然函数近似表达和克拉美-罗限.利用解析的脉冲轮廓,对PSR B1821-24的TOA估计进行了Monte Carlo仿真,讨论了不同观测时间和信噪比下的估计误差,给出了相应的信噪比门限.研究表明:该分析方法能够有效估计X射线脉冲星的TOA定时精度,有利于评估其在各种应用中的性能.
The cycle-stationary Poisson model of photon arrival of X-ray pulsar and pulse time of arrival （TOA） are discussed. Based on this model, the maximum-likelihood es-timate （MLE） of TOA is presented as well as the Cramer-Rao boundary （CRB）, especially for the low-RsN （signal to noise ratio） cases. Using its analytic pulse profile, the Monte Carlo simulation of MLE for PSR B1821-24 is carried out and the timing error performance is analyzed and compared with the theoretical CRB under different observational durations and different RSN. The RSN threshold effect is observed and its significance is discussed. Results show that this method is an effective analysis tool to calculate the TOA precision of X-ray pulsar and would help to evaluate the corresponding performance in other applications.
出处
《天文学报》
CSCD
北大核心
2010年第3期263-271,共9页
Acta Astronomica Sinica
基金
国家自然科学基金(60977054)
陕西省自然科学基金(2010JQ8002)
西安市科技计划项目(CXY1012)
校特色研究项目(105-21091 1)资助
关键词
脉冲星
普通
脉冲星
个别
X射线
双星
方法
数据分析
pulsars
general, pulsars
individual, X-rays
binaries, methods
data analysis
