GHz峰值谱脉冲星统计研究

Statistical research on pulsars with the gigahertz-peaked spectra

GHz峰值谱脉冲星是指其射电谱在1GHz附近会发生倒转的脉冲星。当前已发现有33颗此类脉冲星。这些倒转谱形成的原因可能是由于星际介质对脉冲星的射电辐射所产生的自由-自由吸收引起的。本文对这些脉冲星的倒转谱峰值频率、谱指数、色散量等参数进行了统计研究,发现GHz峰值谱脉冲星的峰值频率主要分布在0.5~1.0 GHz之间,它们的平均谱指数为-1.52,脉冲星的色散量与自转周期有显著的正相关性,这种正相关可能表明星际介质是影响GHz峰值谱脉冲星自转速度的重要因素。本文也讨论了星际介质对GHz峰值谱脉冲星计时的影响。

Pulsars with the gigahertz-peaked spectra(GPS)are named GPS pulsars,which means that the spectra of those pulsars in the radio band will turn over near 1 GHz.There are 33 GPS pulsars discovered so far.The reason causing the turn-over spectra may be due to the free-free absorption of the pulsar’s radio radiation by the interstellar medium.We carry out statistical research on the peak frequency of turn-over spectrum,the spectral index,and the dispersion measure of these GPS pulsars.We find that the distribution of peak frequency of these GPS pulsars is between 0.5 GHz and 1.0 GHz,the average spectral index is-1.52.We also find that there is a strong positive correlation between the dispersion measure and the pulsar’s rotation period,which suggests that the interstellar medium may be an interfering factor of the rotation of GPS pulsars.At last,the effect of intermedium on timing of GPS pulsar is discussed.