3颗脉冲星自转性质的研究

Rotational Properties of Three Pulsars

正常脉冲星和毫秒脉冲星都表现出计时噪声.脉冲星的自转变化是造成计时噪声的重要原因之一.通过联合新疆天文台南山25 m射电望远镜和澳大利亚Parkes 64 m射电望远镜的脉冲到达时间数据,使用脉冲星计时的方法对PSR J1539-5626、J1832-0827和J1847-0402的自转进行分析研究,它们在到达时间残差上均表现出很强的计时噪声,低频噪声的功率谱分别符合谱指数为-6、-6、-4.5的幂律,功率谱强度分别为1.77×10-^17yr^3、4.43×10^-18yr^3和2.09×10^-18yr^3.这3颗脉冲星在自转频率1阶导数的变化上都表现出较为明显的振荡,振荡幅度分别为0.61(3)×10^-15s^-2、0.54(5)×10^-16s^-2和0.11(2)×10^-15s^-2(其中括号内数字代表末位数字的有效误差,下同),自转频率1阶导数振荡变化的相对大小分别是0.75(5)%、0.035(9)%、0.076(2)%.利用Parkes 64 m射电望远镜的观测数据,分别获得了这3颗脉冲星积分脉冲轮廓及其半高全宽,发现3颗脉冲星的脉冲轮廓的宽度均有一定的变化,变化幅度分别为0.0028(6)、0.00059(3)和0.00011(4)个相位.没有探测到自转减慢率的变化与辐射变化之间存在明显的相关性.

Both normal pulsars and millisecond pulsars show timing noises.The variations of rotation are the main reason of timing noises in pulsars.Combining the timing data from the Nanshan 25 m radio telescope and Parkes 64 m radio telescope,we analyze the rotations of PSR J1539-5626,J1832-0827,and J1847-0402 using the pulsar timing method.Strong timing noises dominate the timing residuals of the three pulsars.The slope for the power spectrum of timing noise is-6,-6,and-4.5,respectively,and the intensity of the power spectrum is 1.77×10^-17y^r3,4.43×10^-18yr^3,and 2.09×10^-18yr^3,respectively.These pulsars show fluctuations of spin-down rates,and relative amplitude of the variations in the first derivative of the rotation frequency are 0.75(5)%,0.035(9)%,and 0.076(2)%,respectively(the number in brackets represents the effective error of the last digit).With the data from the Parkes 64 m radio telescope,we estimate the width(full width at half maximum,FWHM)of integrated pulse profiles.These pulsars show obvious variations of pulse profiles,the variation of pulse width is respectively 0.0028(6),0.00059(3),and 0.00011(4)phase.We calculate the correlation coefficient between the rotational parameters and FWHM.It is found that there is no obvious strong association between the spin-down rate and FWHM.