Searching Ultra-compact Pulsar Binaries with Abnormal Timing Behavior
Searching Ultra-compact Pulsar Binaries with Abnormal Timing Behavior
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DOI：
10.3847/1538-4357/aaac34
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发表时间：
2018-03
期刊：
影响因子：
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通讯作者：
B. Gong;Ya-Ping Li;J. Yuan;J. Tian;J. Tian;Yiwei Zhang;Di Li;B. Jiang;X.-D. Li;Huigang Wang;Y. Zou;L. Shao
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文献类型：
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作者：
B. Gong;Ya-Ping Li;J. Yuan;J. Tian;J. Tian;Yiwei Zhang;Di Li;B. Jiang;X.-D. Li;Huigang Wang;Y. Zou;L. Shao
超致密的脉冲星双星既是引力波探测器的理想引力辐射源，也是基础物理实验室的理想来源。然而，目前所有射电脉冲星双星的最短轨道周期为1.6小时。没有较短轨道周期的脉冲星双星很可能是由于技术限制。本文指出，在短轨道周期的脉冲星双星上发生的潮汐效应会对轨道要素产生扰动，并导致轨道调制的显著变化，从而大大降低了广泛使用的加速度搜索的灵敏度。这里提出了一种新的搜索方法。用发生在超紧凑双星上的潮汐效应模拟了单脉冲观测中出现的时间异常残差。异常计时行为中显示的尖峰所代表的主要特征的再现表明，像PSRB0919+06这样的脉冲星可能是轨道周期为∼10分钟的超紧凑双星和白矮星的伴星。通过(1)将预测的长期双星效应与观测到的数十年的计时噪声进行比较，以及(2)观察预期伴星的光学对应物，进一步测试了这种候选恒星的双星性质。测试(1)可能支持我们的模型，而测试(2)需要更多的观察。在不久的将来，通过将这种新方法应用于其他候选二进制文件，可能会发现一些有趣的超紧凑二进制文件。
Ultra-compact pulsar binaries are both ideal sources of gravitational radiation for gravitational wave detectors and laboratories for fundamental physics. However, the shortest orbital period of all radio pulsar binaries is currently 1.6 hr. The absence of pulsar binaries with a shorter orbital period is most likely due to technique limit. This paper points out that a tidal effect occurring on pulsar binaries with a short orbital period can perturb the orbital elements and result in a significant change in orbital modulation, which dramatically reduces the sensitivity of the acceleration searching that is widely used. Here a new search is proposed. The abnormal timing residual exhibited in a single pulse observation is simulated by a tidal effect occurring on an ultra-compact binary. The reproduction of the main features represented by the sharp peaks displayed in the abnormal timing behavior suggests that pulsars like PSR B0919+06 could be a candidate for an ultra-compact binary of an orbital period of ∼10 minutes and a companion star of a white dwarf star. The binary nature of such a candidate is further tested by (1) comparing the predicted long-term binary effect with decades of timing noise observed and (2) observing the optical counterpart of the expected companion star. Test (1) likely supports our model, while more observations are needed in test (2). Some interesting ultra-compact binaries could be found in the near future by applying such a new approach to other binary candidates.