Demonstration of stellar intensity interferometry with the four VERITAS telescopes
Demonstration of stellar intensity interferometry with the four VERITAS telescopes
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DOI：
10.1038/s41550-020-1143-y
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发表时间：
2020-07-20
期刊：
影响因子：
14.1
通讯作者：
Williamson, T. J.
中科院分区：
文献类型：
--
作者：
Abeysekara, A. U.;Benbow, W.;Williamson, T. J.
恒星强度干涉测量（SII）正在复兴。在这里，来自VERITAS阵列的四个1,2米光学反射器的数据被事后关联，以高精度确定两颗恒星的角直径，为未来大型切伦科夫阵列的SII奠定基础。光学波长的高角分辨率观测为恒星天体物理学提供了有价值的见解（1，2），并能够直接测量基本恒星参数（3，4）和恒星大气的探测，拱星盘（5），快速旋转恒星的伸长（6）和造父变星的脉动（7）。大多数恒星的角大小为1毫角秒或更小，要在空间上分辨这种尺度的恒星盘和特征，需要使用基线为数百米的望远镜阵列的光学干涉仪。我们报告的恒星强度干涉测量系统开发的四个VERITAS成像大气切伦科夫望远镜的实施。该系统被用来测量两颗亚毫角秒恒星大犬座β和猎户座β的角直径，精度超过5%。该系统使用离线方法，其中每个望远镜记录的星光强度波动在观察后相关。该技术可以很容易地扩展到几十到几百个望远镜上，提供了一种能力，这种能力已经证明对当前一代的光学振幅干涉测量观测站具有技术挑战性。这项工作证明了使用成像大气切伦科夫望远镜阵列作为强度干涉仪进行天体物理测量的可行性，并显示了在未来的天文台，如切伦科夫望远镜阵列集成强度干涉测量系统的前景。
Stellar intensity interferometry (SII) is undergoing a revival. Here, data from the four 12 m optical reflectors of the VERITAS array are correlated post facto to determine the angular diameter of two stars to a high precision, laying the groundwork for SII at future large Cherenkov arrays.High angular resolution observations at optical wavelengths provide valuable insights into stellar astrophysics(1,2), and enable direct measurements of fundamental stellar parameters(3,4)and the probing of stellar atmospheres, circumstellar disks(5), the elongation of rapidly rotating stars(6)and the pulsations of Cepheid variable stars(7). The angular size of most stars is of the order of one milliarcsecond or less, and to spatially resolve stellar disks and features at this scale requires an optical interferometer using an array of telescopes with baselines on the order of hundreds of metres. We report on the implementation of a stellar intensity interferometry system developed for the four VERITAS imaging atmospheric Cherenkov telescopes. The system was used to measure the angular diameter of the two sub-milliarcsecond stars beta Canis Majoris and epsilon Orionis with a precision of greater than 5%. The system uses an offline approach in which starlight intensity fluctuations that are recorded at each telescope are correlated post observation. The technique can be readily scaled onto tens to hundreds of telescopes, providing a capability that has proven technically challenging to the current generation of optical amplitude interferometry observatories. This work demonstrates the feasibility of performing astrophysical measurements using imaging atmospheric Cherenkov telescope arrays as intensity interferometers and shows the promise for integrating an intensity interferometry system within future observatories such as the Cherenkov Telescope Array.