AI 中文总结
本文对主序射电脉冲辐射体CU Vir开展首次监测，发现其脉冲特性及自转周期，为MRP的时间变化起源研究提供观测依据。
AI 中文摘要
CU Vir是一颗磁热星，也是首个被发现的主序射电脉冲辐射体（MRP），其特征是能通过电子回旋脉泽辐射产生周期性射电脉冲。尽管在理解MRP方面已取得重大进展，但它们的时间特性仍大多未被探索。为克服这一局限，我们利用澳大利亚望远镜致密阵列开展了一项试点研究，在1至3吉赫的频率范围内对CU Vir的脉冲进行了36个历元的观测。在该频率范围内，CU Vir每个自转周期会产生两个圆偏振度约100%的脉冲，称为“前导脉冲”和“后随脉冲”。我们发现两个脉冲的变异性指数随频率存在显著差异，前导脉冲在整个观测频段内表现出更高的变异性。这一结果可通过斜转磁层中的离心 breakout 事件（引发跨频率的相关涨落），以及与相干辐射相关的本征不稳定性来解释。此外，我们还发现脉冲到达相位存在抖动，这一现象需在未来的监测活动中加以考虑。在观测期间，脉冲还表现出向更晚到达时间的系统性偏移，据此我们将自转周期精确到0.5206882天。最后，我们估计提取前导或后随脉冲的全局特性需要约30个脉冲，这一相对较小的数量强烈推动对MRP开展更广泛的监测活动，以验证我们的结果并明确观测到的时间变化的起源。
英文摘要
CU Vir, a magnetic hot star, is the first discovered Main-sequence Radio Pulse emitter (MRP) characterized by its ability to produce periodic radio pulses via electron cyclotron maser emission. Although significant advancements have been made in understanding MRPs, their temporal properties remain mostly unexplored. To overcome this limitation, we conducted a pilot study with the Australia Telescope Compact Array, in which we observed pulses from CU Vir at 36 epochs over $1-3$ GHz. In this frequency range, CU Vir produces two $\approx 100\%$ circularly polarized pulses, called `leading' and `trailing' pulses per rotation period. We find significant differences in the variability indices exhibited by the two pulses as a function of frequencies, with the leading pulse showing higher variability throughout our observing band. This result could be explained in the scenario of centrifugal breakout events in the magnetosphere of an oblique rotator causing correlated fluctuations across frequencies, along with intrinsic instabilities associated with coherent emission. In addition, we discover jittering in the arrival phases of pulses that must be considered in future monitoring campaigns. The pulses also exhibit a systematic shift to later arrival times during the course of our observing campaign, allowing us to refine the rotation period to $0.5206882$ days. Finally, we estimate that $\sim 30$ pulses will be needed to extract global pulse properties for the leading or trailing pulses. This relatively small number strongly motivates more extensive monitoring campaigns of MRPs, both to validate our results, and also to pinpoint the origin of the observed temporal variations.
CommentsAccepted for publication in ApJ
