毫秒脉冲星计时观测进展

Progress on Millisecond Pulsar Timing Observations

在评述国际上毫秒脉冲星长期计时观测成果的基础上,比较了由毫秒脉冲星自转定义的脉 冲星时PT与原子时AT的长期稳定度。毫秒脉冲星PSR B1855+09 15 yr的长期稳定度优于 原子时TAI-USNO,而接近原子时TAI-PTB;其短期稳定度主要受到计时观测误差的限 制。毫秒脉冲星PSR J0437-47 1 yr以上的稳定度明显优于上述两原子时系统。毫秒脉冲星PSR B1937+21和PSR J1713+07的长期稳定度受到低频噪声影响,但仍能对综合脉冲星时PTens的 建立与保持作出贡献。另外,介绍和评述了国际上脉冲星计时阵的现状及发展。随着脉冲星计时阵 的实施,在脉冲星时间标准研究、原子时误差、太阳系历表误差研究和引力波探测方面将会取得重 要成果;展望了国际上平方公里望远镜(SKA)在毫秒脉冲星计时观测方面的发展前景。

Long term timing stability for some millisecond pulsars is reviewed and analyzed. Comparison between PSR B1855+09 timing results from Arecibo and some atomic time scales exhibits that the long term stability of the pulsar σz(T) at T≥15 yr is better than that of atomic time scale TAI-USNO and approaches TAI-PTB. Short term timing behavior for this pulsar is mainly affected by its larger timing error. When more regular timing observations are made and more radio telescopes contribute to timing observations of this pulsar the timing stability of PSR B1855+09 may be further improved. Millisecond pulsar PSR J0437-47 is a perfect celestial clock, its timing stability is obviously better than PSR B1855+09 and some atomic time scales. Long term stabilities of PSR B1937+21 and PSR J1713+07 seem limited by low frequency timing noise. However they may contribute to make an ensemble pulsar time scale. Millisecond pulsar timing array (PTA) has been developed and operated over the world. Uniform distribution on the sky of target millisecond pulsars is needed and some common millisecond pulsars for timing of PTAs are also important to connection of PTAs. Information on errors of atomic time scale and ephemeris may be derived and gravitational wave may be detected from PTAs. In the future, powerful Square Kilometer Array (SKA) will make contribution to both new pulsar search and high precision timing observations for millisecond pulsars.