High-quality averaged radio profiles of some pulsars exhibit double, highly symmetric features both in emission and absorption. It is shown that both types of features are produced by a split-fan beam of extraordinary-mode curvature radiation (CR) that is emitted/absorbed by radially-extended streams of magnetospheric plasma. With no emissivity in the plane of the stream, such a beam produces bifurcated emission components (BFCs) when our line of sight passes through the plane. A distinct example of double component created in that way is present in averaged profile of the 5 ms pulsar J1012+5307. We show that the component can indeed be very well fitted by the textbook formula for the non-coherent beam of curvature radiation in the polarisation state that is orthogonal to the plane of electron trajectory. The observed width of the BFC decreases with increasing frequency at the rate that confirms the curvature origin. Likewise, the double absorption features (double notches) are produced by the same beam of the extraordinary-mode CR, when it is eclipsed by thin plasma streams. The intrinsic property of CR to create bifurcated fan beams explains the double features in terms of very natural geometry and implies the curvature origin of pulsar radio emission. (abbreviated)
Do all millisecond pulsars share a common heritage?
低质量X射线双星系统中中子星毫秒脉动的发现证实了毫秒射电双星与低质量X射线双星系统之间的联系。从那时起，从LMXB产生毫秒射电双星，然后由于偶极辐射而自旋下降的过程被认为是毫秒射电双星的“标准进化”。然而，是否所有观测到的毫秒射电暴都可以由LMXB产生的问题直到现在还没有得到定量的解决。标准的演化过程产生的毫秒周期（P）和自旋下降速率（Pdot）并不完全独立。毫秒级射电望远镜可能达到的P-Pdot值受到联合约束。为了检验观测到的毫秒射电天体是否是毫秒X射线天体（MSXP）的明确后代，我们制作了一张概率图，它代表了标准模型下毫秒射电天体的预期分布。我们以超过95%的置信度表明，在标准模型的框架内，所观测到的毫秒X射线天体不能产生具有高磁场的最快旋转毫秒射电天体，例如PSR B 1937 +21。
