脉冲星射电轮廓中高斯成分在主脉冲和中间脉冲的不同分布

研究了高斯辐射成分在可视点所画出轨迹上的分布,这个可视点因脉冲星的转动而作非匀速度运动.通过假设辐射区域围绕磁轴均匀分布,一个高斯辐射成分便对应于可视轨迹划过的一个辐射区域.因为演示辐射区域在可视轨迹上是不均匀的分布,因此高斯成分沿轨迹也是不均匀的,而高斯成分的密度在磁轴与视线距离最近时为最大.高斯成分的分布取决于脉冲星的两个角度:旋转轴和视线之间的夹角,以及磁轴和旋转轴之间的倾角.基于此模型,一个脉冲星平均轮廓中观察到的多个高斯成分便对应于可视轨迹在特定的转动相位范围内的辐射区域.演示了脉冲星旋转的近侧和远侧的相位,分别对应的主脉冲和中间脉冲,两者高斯成分的数量和分布是不同的.而且还发现,沿可视轨迹上的辐射区域总数与围绕磁轴的辐射区域的总数是不同,并且预测的辐射区域数目会因忽略可见点的运动而明显不同.拟合表明脉冲星轮廓的高斯成分的形状和数量可能与实际构成轮廓的成分的形状和数量不同.以PSR B0826–34的辐射为例,并假设辐射来自单一磁极.

The Different Distribution of Gaussian Components between Mainpulse and Interpulse in Pulsar Radio Profiles

The arrangement of Gaussian emission components along a trajectory traced by a visible point moving at non-uniform speed as the pulsar rotates is investigated. By assuming emission locations confined to spots that arranged evenly around the magnetic axis, a Gaussian emission component corresponds to a cut of an emission spot by the trajectory. The distribution of the emission spots, and hence the Gaussian components, are uneven along the trajectory, being highest around the nearest approach of the magnetic axis to the line of sight, and dependent on two angles of a pulsar: the viewing angle, between the rotation axis and the line of sight, and the obliquity angle, between the magnetic and rotation axes. Observed multiple Gaussian components in a profile then corresponds to several emission spots locating on the trajectory within a specific range of pulsar phase. Demonstration is given to show that the number and distribution of the Gaussian components are different between ranges around the near and far sides of pulsar rotation, corresponding to the mainpulse and interpulse, respectively. The total number of emission spots on a trajectory may be different from that around the magnetic axis, and ignoring the motion of the visible point can lead to significant discrepancy in the predicted number of emission spots. The shape and number of the Gaussian components for fitting a profile may be different from that of the actual components that compose the profile. As an example, the model is applied to the emission arrangement in PSR B0826--34 by assuming the emission comes from a single pole.