RAPID Opportunity for U/V band stellar imaging using intensity interferometry with the VERITAS Observatory

干涉测量法是一种将来自多个望远镜的光结合起来产生具有极高空间分辨率的图像的方法。单靠任何一台望远镜都无法获得如此高的灵敏度。这项具有挑战性的技术可以分辨太阳系外的恒星，尽管它们距离很远。这样的壮举用任何一台望远镜都是不可能的，因为即使是离我们最近的恒星，也仍然被看作是未解决的光点。普通干涉测量法结合光学望远镜信号的振幅来形成图像。这个项目利用了另一种干涉测量法，它利用了光（光子）的量子特性。这种量子方法在20世纪50年代首次被证明。Kieda和合作者通过使用大型、分离良好的光学光收集器和快速、现代的电子设备更新了这种方法。在为期一年的观测活动中，它们将形成35颗明亮恒星的图像。他们将使用VERITAS天文台和他们自己的专用探测器、电子设备和数据连接。这个项目将作为一个技术探路者，可能会导致超高分辨率光学天文学的新制度。该项目将使用汉伯里布朗线（HBT）干涉测量法在紫外/光学波段对恒星进行成像。这种方法利用了强度波动之间的相关性，也称为光子聚束，当不同的探测器观察到相同的源时发生。在该方法中，强度相关时间序列是导出图像的干涉量。这种方法的主要优点是它对大气湍流具有鲁棒性；然而，其固有灵敏度较低，需要大面积的光集热器。它还需要快速的时间分辨率和较长的集成时间。利用HBT进行天文观测是在20世纪60年代。70年代和70年代？在此期间，以1 mas的分辨率测量了30多颗恒星的角直径。这种方法最近在几颗明亮的恒星上用现代探测器和在光子计数系统中运行的电子设备进行了演示。Kieda和合作者将使用VERITAS伽玛射线天文台望远镜来演示强度干涉测量成像。他们已经验证了测量黑体辐射时空聚束的关键技术。他们已经展示了利用合成数据重建图像的能力。他们的方法需要亚纳秒同步的数据采集从多个探测器间隔约100米以上的基线。这个项目有潜力展示一种可扩展的技术，并为超高分辨率的天文光学成像开辟一个广阔的、未开发的前沿。

Interferometry is a method for combining the light from multiple telescopes to generate an image with exceptionally high spatial resolution. Such acuity cannot be obtained by either telescope alone. This challenging technique can resolve stars outside our solar system, despite their very great distances. Such a feat is impossible with any single telescope, for which even the closest stars are still seen as unresolved points of light. Ordinary interferometry combines the amplitudes of optical telescope signals to form an image. This project utilizes another kind of interferometry that makes use of the quantum nature of light (photons). This quantum approach was first demonstrated in the 1950?s. Kieda and collaborators update this approach by using large, well-separated optical light collectors and fast, modern electronics. They will form images of 35 bright stars over the course of a one-year observing campaign. They will use the VERITAS Observatory and their own dedicated detectors, electronics and data connectivity. This project will serve as a technology pathfinder that may lead to a new regime in ultra-high resolution optical astronomy.This project will image stars in the UV/Optical bandpass using the method of Hanbury Brown Twiss (HBT) interferometry. This method utilizes the correlation between intensity fluctuations, also called photon bunching, that occurs when different detectors observe the same source. In this method, the intensity correlation time series is the interferometric quantity upon which images are derived. The main advantage of this method is that it is robust to atmospheric turbulence; however, its low inherent sensitivity demands large-area light collectors. It also requires fast time resolution and long integration times. Astronomical observations using HBT were done in the 1960?s and 1970?s during which time the angular diameters of more than 30 stars were measured with a resolution of 1 mas. This method was recently demonstrated on several bright stars with modern detectors and electronics operating in the photon-counting regime. Kieda and collaborators will use the VERITAS gamma-ray observatory telescopes to demonstrate imaging with intensity interferometry. They have validated key technologies for measuring spatial and temporal bunching of blackbody radiation. They have demonstrated the ability to reconstruct images using synthetic data. Their method requires sub-nanosecond synchronization of the data acquisition from multiple detectors spaced at ~100+ meter baselines. This project has the potential to demonstrate a scalable technology and open a wide, unexplored frontier for astronomical, optical imaging with ultra-high resolution.