脉冲星J0437-4715的长期稳定度计时分析

Analysis on Long - term Timing Stability of PSR J0437 -4715

PSRJ0437-4715既是一颗自转极其稳定的毫秒脉冲星.在射电观测与X射线频段皆有福射信号,也是一颗适于空间导航的脉冲星。本文首先从脉冲星时空基准建立的需求出发,分析澳大利亚Parkes射电望远镜脉冲星计时阵(PPTA)项目对J0437-4715历时13年的多终端观测原始数据;然后,经过原始数据转换、观测轮廓提取、脉冲到达时间(TOA)计算及星历参数拟合,获得一个脉冲星星历,拟合后的参数与国际最新结果比较,在赤经上差异小于3.2×10^-2mas,在赤纬上小于4.4×10^-2mas,自转频率小于3.46×10^-12Hz,验证了本文处理方法的正确性;最后,使用方差评估PSRJ0437-4715的长期稳定性,其稳定性随时间增加而提高,该脉冲星1年稳定度为10小工,而13年稳定度提髙至10^-15.3,且没有发现长期漂移现象.

PSR J0437-4715 is a very stable millisecond pulsar with a radiated signal both in radio observation and X-ray bands. It is also a pulsar suitable for space navigation.In this paper, the 13-year pulsar multi - tenninal observation raw data of the Australian Parkes Radio Telescope Pulsar Timed Array (PPTA) project is analyzed and processed. A pulsed star calendar is obtained after the original data is transformed, observed profile is extracted, pulse arrival time (TOA) is calculated and ephemeris parameters fitting are completed. The results show that the differences between parameters fitted and the latest international results is less than 3.2×10^-3mas in the right ascension, 4.4×10^-2mas in the declination, and 3.46 × 10^-12 Hz in the rotation frequency , and it proves the correctness of the proposed method. Finally, the long-term stability of J0437-4715 is evaluated by variance.It shows that its stability is improved as time increases, and the stability of pulsar time scale can reach 10^-13.8 xin 1 year and 10^-15.3 in 13 years, also no long - tenn drift has been observed.