The NANOGrav 11-year Data Set: High-precision Timing of 45 Millisecond Pulsars
The NANOGrav 11-year Data Set: High-precision Timing of 45 Millisecond Pulsars
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DOI：
10.3847/1538-4365/aab5b0
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发表时间：
2018-04-01
影响因子：
8.7
通讯作者：
Zhu, Weiwei
中科院分区：
文献类型：
--
作者：
Arzoumanian, Zaven;Brazier, Adam;Zhu, Weiwei
我们在长达11年的时间跨度内为45毫秒的引力波观测提供了高精度的计时数据，作为北美纳赫兹引力波观测站（NANOGrav）项目的一部分，旨在检测和表征低频引力波。阿雷西博天文台和/或绿色银行望远镜在327兆赫至2.3千兆赫的频率范围内观测到了这些双星。大多数卫星的观测频率约为每月一次，每周观测6次高定时精度卫星。所有的观测都是在每个观测时期以相隔很远的频率进行的，以适应时变的色散延迟。我们描述了我们的数据处理方法，到达时间（TOA）的计算，并实现了一个新的，自动化的方法来消除离群TOA。我们适合每个脉冲星的定时模型，包括自旋，天体测量，（对于双星）轨道参数;时变色散延迟;和参数，量化脉冲轮廓随频率的演变。定时解决方案提供了三个新的视差测量，两个新的夏皮罗延迟测量，和两个新的测量显着的轨道周期变化。我们拟合模型，每个脉冲星的噪声源的特征。我们发现，11颗星显示出显著的红噪声，光谱指数通常小于非回收星的典型测量值，这可能表明它们的起源不同。另一篇论文使用这些数据来限制引力波背景的强度。
We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project, aimed at detecting and characterizing low-frequency gravitational waves. The pulsars were observed with the Arecibo Observatory and/or the Green Bank Telescope at frequencies ranging from 327 MHz to 2.3 GHz. Most pulsars were observed with approximately monthly cadence, and six high-timing-precision pulsars were observed weekly. All were observed at widely separated frequencies at each observing epoch in order to fit for time-variable dispersion delays. We describe our methods for data processing, time-of-arrival (TOA) calculation, and the implementation of a new, automated method for removing outlier TOAs. We fit a timing model for each pulsar that includes spin, astrometric, and (for binary pulsars) orbital parameters; time-variable dispersion delays; and parameters that quantify pulse-profile evolution with frequency. The timing solutions provide three new parallax measurements, two new Shapiro delay measurements, and two new measurements of significant orbital-period variations. We fit models that characterize sources of noise for each pulsar. We find that 11 pulsars show significant red noise, with generally smaller spectral indices than typically measured for non-recycled pulsars, possibly suggesting a different origin. A companion paper uses these data to constrain the strength of the gravitational-wave background.