An Optical Bench to Weigh Cosmic Structure

暗物质和暗能量在很大程度上仍然神秘，因为--顾名思义--它们很难被看到。然而，即使我们无法直接观察到这个暗区域，我们也可以观察到暗物质和暗能量对宇宙中其他物体的影响。最好的方法之一是利用强引力透镜--阿尔伯特·爱因斯坦的相对论预言的光在大质量物体周围的弯曲。引力透镜就像是宇宙望远镜，望远镜透镜的强度是由暗物质决定的，而‘望远镜管’的长度和望远镜与它所放大的距离源之间的距离是由暗能量驱动的宇宙的膨胀决定的。要发现暗物质和暗能量是如何使这些望远镜工作的，需要首先在天空中发现它们，而且像所有的望远镜一样，它们必须得到精确的校准。我的研究使用大型公共调查来发现镜片(我正在动物园添加的新镜片是鳗鱼和Cassowarys)，我使用光谱跟踪观察来独立了解镜片的特性。这些数据使我能够确定透镜的强度，类似于从望远镜中取出透镜来测量其曲率--知道曲率意味着知道暗物质在透镜中的位置。一旦透镜被校准，对它所观测到的源的大小的观测有助于确定这些物体之间的相对距离。由于暗能量导致宇宙加速膨胀，相对距离越大意味着暗能量越多，而距离越小意味着暗能量越少；有了足够多的观察源，暗能量的历史就可以绘制出来。这些经过适当校准的引力透镜望远镜已经观测到了暗物质和暗能量！

Dark matter and dark energy remain largely mysterious because -- as their name implies -- they are difficult to see. However, even if we are unable to observe this dark sector directly, we can observe the effects that dark matter and dark energy have on other objects in the Universe. One of the best ways to do this is with strong gravitational lensing -- the bending of light around massive objects that was predicted by Albert Einstein's theory of relativity. Gravitational lenses act as cosmic telescopes, and the strength of the telescope lens is set by dark matter, while the length of the `telescope tube' and the distance between the telescope and the distance source it is magnifying are set by the expansion of the Universe that is driven by dark energy. Uncovering how dark matter and dark energy make these telescopes work requires that they first be found on the sky and, like all telescopes, they must be precisely calibrated. My research employs large public surveys to discover lenses (the new lenses I am adding to the zoo are EELs and CASSOWARYs), and I use spectroscopic follow-up observations to independently learn more about the lens properties. These data allow me to determine the strength of the lens, similar to removing a lens from a telescope to measure its curvature -- and knowing the curvature means knowing where the dark matter is in the lens. Once a lens is calibrated, observations of the sizes of sources it is observing help to pin down relative distances between these objects. Because dark energy causes accelerated expansion of the Universe, larger relative distances imply more dark energy, while smaller distances imply less; with a large enough number of observed sources, the history of dark energy can be mapped out. These properly-calibrated gravitational lens telescopes have `observed' dark matter and dark energy!