Alongside the population of several hundred radio millisecond pulsars currently known in Milky Way globular clusters, a subset of six slowly spinning pulsars (spin periods 0.3–4 s) are also observed. With inferred magnetic fields ≳1011 G and characteristic ages ≲108 yr, explaining the formation of these apparently young pulsars in old stellar populations poses a major challenge. One popular explanation is that these objects are not actually young but instead have been partially spun up via accretion from a binary companion. In this scenario, accretion in a typical low-mass X-ray binary (LMXB) is interrupted by a dynamical encounter with a neighboring object in the cluster. Instead of complete spin-up to millisecond spin periods, the accretion is halted prematurely, leaving behind a “partially recycled” neutron star. In this Letter, we use a combination of analytic arguments motivated by LMXB evolution and N-body simulations to show that this partial recycling mechanism is not viable. Realistic globular clusters are not sufficiently dense to interrupt mass transfer on the short timescales required to achieve such slow spin periods. We argue that collapse of massive white dwarfs and/or neutron star collisions are more promising ways to form slow pulsars in old globular clusters.

中文翻译：

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银河系球状星团中的慢脉冲星可以通过部分回收形成吗？


除了目前在银河系球状星团中已知的数百颗射电毫秒脉冲星的数量外，还观察到了六颗缓慢旋转的脉冲星（自旋周期 0.3-4 秒）的子集。根据推断的磁场 ≳1011 G 和特征年龄 ≲108 年，解释这些明显年轻的脉冲星在老恒星群中的形成是一个重大挑战。一种流行的解释是，这些天体实际上并不年轻，而是通过双星伴星的吸积部分自旋而来。在这种情况下，典型的低质量 X 射线双星 （LMXB） 中的吸积被与星团中相邻物体的动力学相遇打断。吸积不是完全自旋到毫秒级的自旋周期，而是提前停止，留下“部分回收”的中子星。在这封信中，我们结合了由 LMXB 进化和 N 体模拟驱动的分析论点，以证明这种部分回收机制是不可行的。现实的球状星团的密度不足以在实现如此缓慢的自旋周期所需的短时间尺度上中断质量传递。我们认为，大质量白矮星的坍缩和/或中子星碰撞是在旧球状星团中形成慢脉冲星的更有希望的方法。