Recently, two ultralong-period radio transients, GLEAM-X J162759.5-523504.3 (J1627) and GPM J1839-10 (J1839), were discovered with spin periods longer than 1000 s. The origin of these two ultralong-period radio transients is intriguing in understanding the spin evolution of neutron stars (NSs). In this work, we examine whether the interaction between strong magnetized NSs and fallback disks can spin NSs down to the observed ultralong period. Our simulations found that the magnetar + fallback disk model can account for the observed period, period derivative, and X-ray luminosity of J1627 in the quasi-spin-equilibrium stage. To evolve to the current state of J1627, the initial mass-accretion rate of the fallback disk and the magnetic field of the NS are in the range of (1.1–30) × 10²⁴ g s⁻¹ and (2–5) × 10¹⁴ G, respectively. In the active lifetime of the fallback disk, it is impossible for J1839 to achieve the observed upper limit of the period derivative. Therefore, we propose that J1839 may be in the second ejector phase after the fallback disk becomes inactive. Those NSs with a magnetic field of (2–6) × 10¹⁴ G and a fallback disk with an initial mass-accretion rate of ∼10²⁴–10²⁶ g s⁻¹ are possible progenitors of J1839.

中文翻译：

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超长周期无线电瞬变的进化起源


最近，发现了两个超长周期射电瞬变，GLEAM-X J162759.5-523504.3（J1627）和GPM J1839-10（J1839），其自旋周期超过1000秒。这两个超长周期射电瞬变的起源对于理解中子星（NS）的自旋演化非常有趣。在这项工作中，我们研究了强磁化 NS 和回退盘之间的相互作用是否可以使 NS 旋转至观察到的超长周期。我们的模拟发现，磁星+后备盘模型可以解释J1627在准自旋平衡阶段的观测周期、周期导数和X射线光度。为了演化到 J1627 目前的状态，后备盘的初始质量吸积率和 NS 的磁场范围为 (1.1–30) × 10 ²⁴ g s ⁻¹ G。在后备盘的有效寿命内，J1839不可能达到观察到的周期导数上限。因此，我们建议J1839在后备盘变为非活动状态后可能处于第二喷射阶段。那些磁场为 (2–6) × 10 ¹⁴ G 和初始质量吸积率为 ∼10 ²⁴ –10 ²⁶ 可能是 J1839 的祖先。