Refined Mass and Geometric Measurements of the High-mass PSR J0740+6620
Refined Mass and Geometric Measurements of the High-mass PSR J0740+6620
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DOI：
10.3847/2041-8213/ac03b8
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
E. Fonseca;H. Cromartie;T. Pennucci;P. Ray;A. Kirichenko;S. Ransom;P. Demorest;I. Stairs;Z. A
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文献类型：
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作者：
E. Fonseca;H. Cromartie;T. Pennucci;P. Ray;A. Kirichenko;S. Ransom;P. Demorest;I. Stairs;Z. A
我们报告PSR J 0740 +6620的持续定时观测结果，PSR J 0740 +6620是一颗高质量、2.8毫秒的射电脉冲星，在轨道上有一颗可能是超冷白色矮星伴星。我们的数据集由100米绿色银行望远镜和加拿大氢强度测绘实验望远镜的组合脉冲到达时间测量。我们探讨了广义相对论动力学和脉冲色散的变化所产生的基于时间的现象的意义。当使用各种统计方法时，我们发现将1.5年的额外高节奏计时数据与之前的测量结果相结合，证实并改进了之前对PSR J 0740 +6620系统内相对论效应的估计，脉冲星质量mp=2.08−0.07+0.07M <$（68.3%可信度）由相对论夏皮罗时间延迟确定。对于第一次，我们测量长期变化的轨道周期，并认为，这种效果产生明显的横向运动由于加速度。在银河系势中加入了银河系的微分自转和离面加速度的贡献后，我们得到了依赖于模型的距离d=1.14−0.15+0.17 kpc（68.3%可信度）。这一改进的距离证实了从最近的光学观测中确定的白色矮星伴星的超冷性质。我们讨论了下一代设施未来观测的前景，这可能会在未来几年内将J 0740 +6620的m p精度提高一个数量级。
We report results from continued timing observations of PSR J0740+6620, a high-mass, 2.8 ms radio pulsar in orbit with a likely ultracool white dwarf companion. Our data set consists of combined pulse arrival-time measurements made with the 100 m Green Bank Telescope and the Canadian Hydrogen Intensity Mapping Experiment telescope. We explore the significance of timing-based phenomena arising from general relativistic dynamics and variations in pulse dispersion. When using various statistical methods, we find that combining ∼1.5 yr of additional, high-cadence timing data with previous measurements confirms and improves on previous estimates of relativistic effects within the PSR J0740+6620 system, with the pulsar mass mp=2.08−0.07+0.07M⊙ (68.3% credibility) determined by the relativistic Shapiro time delay. For the first time, we measure secular variation in the orbital period and argue that this effect arises from apparent acceleration due to significant transverse motion. After incorporating contributions from Galactic differential rotation and off-plane acceleration in the Galactic potential, we obtain a model-dependent distance of d=1.14−0.15+0.17 kpc (68.3% credibility). This improved distance confirms the ultracool nature of the white dwarf companion determined from recent optical observations. We discuss the prospects for future observations with next-generation facilities, which will likely improve the precision on m p for J0740+6620 by an order of magnitude within the next few years.