低能损率射电脉冲星辐射研究

Radiation Study on the Radio Pulsars with a Low Spin-down Energy Loss Rate

脉冲星辐射理论认为,当中子星旋转磁场产生的感应电场及电压降低,以致不能产生足够多的正负电子对时,其射电辐射将消失,即"死亡".统计分析了34颗"死亡线"以下源,即低能损率射电脉冲星的空间分布及自转周期等物理性质.首先,这类脉冲星都是场星,与特殊种类脉冲星和高能辐射脉冲星没有明显的相关性;其次,这类脉冲星大多分布在低银纬和距离太阳系较近的区域;再次,这类脉冲星具有较大的特征年龄和较长的自旋周期;最后,这类脉冲星1400 MHz射电光度L1400和自转能损率˙E弱相关.低能损率射电脉冲星可能是由于星体通过辐射损失能量,导致自转减慢,自转能损率降低至"死亡线"以下.建议对于低能损率射电脉冲星的搜寻,应针对银河系场中年老的、长周期的射电源,而无需针对特殊种类的脉冲星,也无需针对特殊的空间位置.目前我国正在运行的500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)具有较高的灵敏度,有望观测到更多低能损率射电脉冲星.

The radiation theory of pulsar suggests that when the induced electric?eld and voltage caused by the rotated magnetic?eld of the neutron star decrease,which can not produce enough electron and positron pairs,the radio radiation of the pulsar will disappear,i.e.,'die'.This paper analyzes the space distributions and the physical properties such as the spin periods of the 34 sources under the'death line',i.e.,the radio pulsars with a low spin-down energy loss rate.Firstly,these pulsars are all in the galactic?eld,which show no obvious correlation with the special types of pulsars and the pulsars with a high-energy radiation;Secondly,these pulsars locate in the low galactic latitude and near the solar system;Thirdly,these pulsars show the relative larger characteristic ages and larger spin periods;Last,the radio luminosity of 1400 MHz and the spin-down power˙E of these pulsars show a weak correlation.We argue that the radio pulsars with a low spin-down power may loss energy due to radiation,causing the deceleration of the spin,whose˙E decreases below the'death line'.We suggest that the survey for the radio pulsars with a low spin-down power should focus on the old and long spin period radio sources in the galactic?eld,and it is unnecessary to focus on the special type of the pulsars or the certain spatial positions.The Five-hundred-meter Aperture Spherical radio Telescope(FAST)running at present in our country has the relatively higher sensitivity,which is supposed to observe more radio pulsars with a low spin-down power.