标题： 脉冲星定时阵列探测引力波的多功能方向搜索 显示英文标题

标题： Versatile Directional Searches for Gravitational Waves with Pulsar Timing Arrays

摘要： 通过多年定期监测最稳定的毫秒脉冲星，脉冲星定时阵列（PTAs）能够探测并研究这些脉冲星的计时行为中的相关性。 来自超大质量黑洞双星（SMBHBs）的引力波（GWs）是这种相关性的令人兴奋且可能被探测到的来源。 我们描述了一种简单直接的技术，通过该技术，PTA 可以“同步”形成来自天空特定方向的引力波两极化模式的时间序列。 我们的技术无需对引力波信号的时间域行为做出任何假设。 此方法已用于对单个圆形轨道 SMBHB 的引力波施加严格的限制。 在这里，我们描述了该方法论，并展示了该技术在搜索各种引力波信号（包括具有未建模波形的突发信号）方面的多功能性。 利用帕克斯脉冲星定时阵列的前六年数据，我们进行了全天空搜索，寻找来自任何方向的可检测到的引力波功率过剩。 对于几个附近大型星系团的视线方向，我们进行了更详细的搜索，寻找具有记忆效应的引力波爆发，这是 SMBHB 合并的独特标志。 在所有情况下，我们都发现数据与噪声一致。 显示英文摘要

摘要： By regularly monitoring the most stable millisecond pulsars over many years, pulsar timing arrays (PTAs) are positioned to detect and study correlations in the timing behaviour of those pulsars. Gravitational waves (GWs) from supermassive black hole binaries (SMBHBs) are an exciting potentially detectable source of such correlations. We describe a straight-forward technique by which a PTA can be "phased-up" to form time series of the two polarisation modes of GWs coming from a particular direction of the sky. Our technique requires no assumptions regarding the time-domain behaviour of a GW signal. This method has already been used to place stringent bounds on GWs from individual SMBHBs in circular orbits. Here, we describe the methodology and demonstrate the versatility of the technique in searches for a wide variety of GW signals including bursts with unmodeled waveforms. Using the first six years of data from the Parkes Pulsar Timing Array, we conduct an all-sky search for a detectable excess of GW power from any direction. For the lines of sight to several nearby massive galaxy clusters, we carry out a more detailed search for GW bursts with memory, which are distinct signatures of SMBHB mergers. In all cases, we find that the data are consistent with noise.