解释一下：On September 14, 2015 at 09:50:45 UTC, the LIGO Hanford, WA, and Livingston, LA, observatories detected the coincident signal GW150914 shown in Fig. 1. The initial detection was made by low-latency searches for generic gravitational-wave transients [41] and was reported within three minutes of data acquisition [43]. Subsequently, matched-filter analyses that use relativistic models of compact binary waveforms [44] recovered GW150914 as the most significant event from each detector for the observations reported here. Occurring within the 10-ms intersit propagation time, the events have a combined signal-tonoise ratio (SNR) of 24 [45].

这段文字描述了2015年9月14日UTC时间09:50:45，LIGO Hanford, WA以及 Livingston, LA观测站同时探测到了一个名为GW150914的引力波信号。这个事件是通过对引力波的普通短暂信号进行低延迟搜索得到的，数据采集后不到三分钟就报告了初步检测结果。随后，使用相对论模型匹配滤波分析，从每个探测器的观测数据中发现了GW150914信号，成为本次观测中最显著的事件。这两个事件的时间间隔小于10ms，它们的信噪比（SNR）的组合值为24。