[论文解读] GWTC-2.1: Deep Extended Catalog of Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run

The LIGO Scientific Collaboration, The Virgo Collaboration+1430 more|arXiv (Cornell University)|Aug 2, 2021

Pulsars and Gravitational Waves Research参考文献 243被引用 196

一句话总结

这篇论文提出了一个扩展的目录（GWTC-2.1），记录了LIGO和Virgo在O3前半段期间检测到的紧致双星合并产生的引力波事件，包括更深入的搜索和重新分析，以丰富事件名册。

ABSTRACT

The second Gravitational-Wave Transient Catalog reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15:00 UTC and 1 October 2019 15:00 UTC. We present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the astrophysical probability for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have an astrophysical probability greater than 0.5. Of these candidates, 36 have been reported in GWTC-2. If the 8 additional high-significance candidates presented here are astrophysical, the mass range of events that are unambiguously identified as binary black holes (both objects $\geq 3M_\odot$) is increased compared to GWTC-2, with total masses from $\sim 14 M_\odot$ for GW190924_021846 to $\sim 182 M_\odot$ for GW190426_190642. The primary components of two new candidate events (GW190403_051519 and GW190426_190642) fall in the mass gap predicted by pair instability supernova theory. We also expand the population of binaries with significantly asymmetric mass ratios reported in GWTC-2 by an additional two events (the mass ratio is less than $0.65$ and $0.44$ at $90\%$ probability for GW190403_051519 and GW190917_114630 respectively), and find that 2 of the 8 new events have effective inspiral spins $χ_\mathrm{eff} > 0$ (at $90\%$ credibility), while no binary is consistent with $χ_\mathrm{eff} < 0$ at the same significance.

研究动机与目标

• 改进第三次观测运行的前半段（O3a）引力波事件目录的完整性与深度的动机。
• 提供由 LIGO 和 Virgo 网络检测到的紧致双星合并的更深入、更加完整的清单。
• 对参数估计和选择效应进行改进，以实现对总体和天体物理推断的稳健性。
• 为未来多信使跟进和与扩展的 GW 样本的相关研究提供支持。

提出的方法

• 应用深度搜索和再分析技术，以包括阈值以下或先前遗漏的事件。
• 整合 LIGO 和 Virgo 探测器的数据，构建一个全面的目录。
• 在扩展数据集上进行一致的参数估计和事件验证。
• 描述选择效应与完整性，以支持总体推断。
• 提供标准化的元数据与来源信息，以支持后续分析。

实验结果

研究问题

• RQ1 使用更深层的搜索方法时，在第三次观测运行前半段中有多少紧致双星合并事件？
• RQ2 扩展目录中事件的更新源属性估计（质量、自旋、距离）是什么？
• RQ3 更深的目录如何改变由 LIGO 和 Virgo 观测到的合并的总体推断和事件率估计？
• RQ4 与先前版本相比，GWTC-2.1 目录的选择效应和完整性特征是什么？
• RQ5 扩展目录如何支持未来的多信使与跟进研究？

主要发现

• GWTC-2.1 提供了 O3a 期由 LIGO 和 Virgo 检测到的紧致双星合并的更深扩展目录。
• 本文整合了更精细的参数估计和比以往目录更广泛的事件集。
• 扩展目录通过考虑更深的搜索，使总体及速率推断更加稳健。
• 本工作强调一致的验证与元数据对于可重复性和下游使用的重要性。
• 该目录为多信使跟进和跨信使研究在引力波天文学中的应用提供资源。