THE NANOGRAV NINE-YEAR DATA SET: OBSERVATIONS, ARRIVAL TIME MEASUREMENTS, AND ANALYSIS OF 37 MILLISECOND PULSARS
THE NANOGRAV NINE-YEAR DATA SET: OBSERVATIONS, ARRIVAL TIME MEASUREMENTS, AND ANALYSIS OF 37 MILLISECOND PULSARS
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DOI：
10.1088/0004-637x/813/1/65
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发表时间：
2015-11-01
影响因子：
4.9
通讯作者：
Zhu, Weiwei
中科院分区：
文献类型：
--
作者：
Arzoumanian, Zaven;Brazier, Adam;Zhu, Weiwei
作为北美纳赫兹引力波天文台（NANOGrav）项目的一部分，我们对使用绿色班克和阿雷西沃射电望远镜监测的37毫秒脉冲星进行了长达9年的高精度计时观测。我们描述了用于收集数据的观测和仪器设置，以及用于计算脉冲到达时间的方法;这些方法包括用于测量仪器偏移和表征低信噪比计时结果的新方法。到达时间数据适合于每个源的物理定时模型，包括表征时变色散测量和频率相关脉冲形状演变的项。结合时序模型拟合，我们对每个源的参数化时序噪声模型进行了贝叶斯分析，并在其中10个源中检测到过量低频或“红色”时序噪声的证据。对于其中5种情况，这可能是由于星际介质传播效应，而不是星际自旋变化。本系列的后续论文将对该数据集进行进一步分析，旨在检测或限制纳赫兹频率引力波信号的存在。
We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We describe the observational and instrumental setups used to collect the data, and methodology applied for calculating pulse times of arrival; these include novel methods for measuring instrumental offsets and characterizing low signal-to-noise ratio timing results. The time of arrival data are fit to a physical timing model for each source, including terms that characterize time-variable dispersion measure and frequency-dependent pulse shape evolution. In conjunction with the timing model fit, we have performed a Bayesian analysis of a parameterized timing noise model for each source, and detect evidence for excess low-frequency, or "red," timing noise in 10 of the pulsars. For 5 of these cases this is likely due to interstellar medium propagation effects rather than intrisic spin variations. Subsequent papers in this series will present further analysis of this data set aimed at detecting or limiting the presence of nanohertz-frequency gravitational wave signals.