Detector Characterization to Enable Discovery of Gravitational Waves with Advanced LIGO

爱因斯坦发现的广义相对论告诉我们，我们日常所熟悉的引力其实是某种更奇怪的东西的表现：物质对时空几何形状的弯曲。该理论的关键预测包括宇宙膨胀和黑洞的存在，其中包括引力波（GW）的存在：在大质量的快速运动引起的时空几何中以光速运动的涟漪。虽然引力波对致密双星系统的间接影响已经得到了很好的验证，但直接探测地球上的引力波仍然是一个突出的挑战。实现这种能力的科学回报将是巨大的——从探测爆炸恒星的极端动力学到收集关于宇宙大爆炸时刻的状态的信息。这扇探索宇宙的新窗口耗费了数十年的实验和技术发展，突破了物理科学不同领域的界限。2015年将标志着引力波物理学备受期待的分水岭时刻：两个先进的激光干涉引力波天文台（aLIGO）探测器将开始它们的初始数据采集运行，随后是欧洲先进的处女座引力波天文台的调试。aLIGO探测器的灵敏度将提高到第一代探测器的10倍左右，为观测GW源打开了比以前大1000倍的空间体积。锡拉丘兹小组将支持LIGO科学合作组织对由中子星和/或黑洞组成的双星系统（称为紧凑型双星合并，或“CBC”）的引力波信号的搜索。它的特别重点将是研究仪器人工制品（称为“小故障”）模拟真实信号的方式，并开发新的工具来区分小故障和真实信号。由于双星的引力波可以很好地预测，一些特殊的技术已经被开发出来，以帮助做出区分。然而，这些方法还不足以用先进的LIGO观测到所有的双星。锡拉丘兹大学的研究小组将开发新的工具来处理这些更容易受到攻击的信号。锡拉丘兹小组将支持先进的LIGO（“aLIGO”）在其第一次观测运行（称为“O1”）中搜索CBC信号，有三种基本方法。首先，他们将调整、运行和应用称为“每日CBC”的特殊诊断工具，该工具可以快速反馈aLIGO数据与高斯性的任何偏差。其次，他们将开发一个新的、专门针对LIGO标准工具的版本，用于研究故障与候选信号之间的统计相关性。由于CBC信号的持续时间很长，在询问故障是否与CBC信号在时间上一致之前，有必要实现调谐时移方法。最后，他们将使用相关技术实施一项新的统计测试，以衡量产生候选信号的数据是更像真实信号还是更像故障。这些技术将使在O1（及其他）中搜索CBC信号发挥其潜力，使aLIGO更有可能成功探测到这些迷人物体的信号。

The General Theory of Relativity discovered by Einstein tells us that the familiar, everyday force of gravity is a manifestation of something much stranger: the bending of the geometry of space-time by matter. Among the key predictions of the theory, which includes the expanding Universe and the existence of black holes, is the existence of gravitational waves (GW): ripples moving at the speed of light in the geometry of space-time caused by the fast motion of large masses. Although well tested in terms of their indirect effects on binary systems of compact stars, the direct detection of gravitational waves incident on Earth poses an outstanding challenge. The scientific rewards from achieving this ability would be enormous - ranging from probing the extreme dynamics of exploding stars to gleaning information about the state of the Universe almost at the moment of the Big Bang itself. The effort to enable this new window on the universe has occupied several decades of experimental and technological developments that have pushed the boundaries across diverse fields in the physical sciences. The year 2015 will mark a highly-anticipated watershed moment for gravitational-wave physics: The two advanced Laser Interferomenter Gravitational Wave Observatory (aLIGO) detectors will start their initial data taking runs, followed by the commissioning of the advanced Virgo gravitational wave observatory in Europe. The sensitivity of the aLIGO detector will be ramped up to become about ten times better than that of the first-generation detectors, opening up a spatial volume for observing GW sources that will be 1000 times larger than before. The Syracuse group will support the LIGO Scientific Collaboration's search for gravitational wave signals from binary star systems consisting of neutron stars and/or black holes (called compact binary coalescences, or "CBC's"). Its special focus will be to study the ways in which instrumental artifacts (called "glitches") can mimic genuine signals, and to develop new tools to distinguish glitches from genuine signals. Because the gravitational waveforms from binaries can be very well predicted, some special techniques have already been developed that help make the distinction. However, these methods do not suffice for the full range of binaries expected to be seen with Advanced LIGO. The Syracuse group will develop new tools that will work on these more vulnerable kinds of signals. The Syracuse group will support the search with Advanced LIGO ("aLIGO") for CBC signals in its first observing run (called "O1") with three basic approaches. Firstly, they will tune, run, and apply the special diagnostic tool called "Daily CBC", which gives rapid feedback to commissioners on any departures of aLIGO data from Gaussianity. Secondly, they will develop a new specially-focused version of LIGO's standard tool for investigating the statistical correlation between glitches and candidate signals, hveto; because of the long duration of CBC signals, it is necessary to implement a tuned time-shift method before asking if a glitch is coincident in time with a CBC signal. Finally, they will use related technology to implement a new statistical test that measures whether the data yielding a candidate signal looks more like a true signal or like a glitch. These techniques will enable searches for CBC signals in O1 (and beyond) to live up to their potential, making it substantially more likely that aLIGO will be succeed in detecting signals from these fascinating objects.