Collaborative Research: Building an Event Horizon Telescope: (Sub)millimeter VLBI from the South Pole Telescope

合作研究：建造事件视界望远镜：来自南极望远镜的（亚）毫米VLBI

• 批准号: 1207730
• 负责人: John Carlstrom
• 金额: $ 12.01万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207730&HistoricalAwards=false
• 关键词: Collaborative; Research; Building; Event; Horizon

A research topic of great current interest is the supermassive black hole of about 4 million solar masses that is now known to exist at the center of our Milky Way galaxy. Similar objects are common in other galaxies. Most of what is known about the Milky Way's exotic object comes from studies of the kinematics of stars influenced by its strong gravitational field. No possibility has heretofore existed for directly imaging the black hole, or more technically its event horizon, the gravitational "point of no return" from within which no particle or photon can escape the black hole. The galactic center region is distant, about 8 kpc, making it extraordinarily difficult to obtain high-spatial-resolution images of the supermassive black hole by any direct technique. If such images could be obtained, they would be the very first of their kind, and could reveal information not yet imagined about black holes and the dynamics in the cores of galaxies. To attack this challenging scientific problem, Drs. D. Marrone of the University of Arizona, S. Doeleman of the Northeast Radio Observatory Corporation, and J. Carlstrom of the University of Chicago intend to enhance an existing array of radio telescopes operating at the very highest radio frequencies (the submillimeter, with wavelengths somewhat shorter than a millimeter) and in a mode where telescopes separated by continental baselines coherently combine their data to achieve unprecedented spatial resolution. The general technique is termed Very Long Baseline Interferometry, or VLBI, and the particular array of radio telescopes to be used is referred to as the Event Horizon Telescope (EHT), developed in part through a previous award from NSF. Through a new NSF proposal the researchers plan to add the South Pole Telescope (SPT) as a new station to the EHT. Adding stations (telescopes) in this manner enhances sensitivity to radio signals and also improves the spatial response of the instrument as an imaging device, so that better-quality maps may be made of fainter objects. In addition to the addition of a key observing station, the technology will feature a new, sensitive dual-band millimeter-wave VLBI receiver, optimized for the needs of this project, that will employ superconducting mixer technology developed for the Atacama Large Millimeter Array (ALMA) project by the National Radio Astronomy Observatory (NRAO). Finally, the proven 230 GHz design will be adapted for use at 345 GHz.Funding for this work is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.

目前人们非常感兴趣的一个研究课题是大约 400 万太阳质量的超大质量黑洞，目前已知它存在于我们银河系的中心。 类似的天体在其他星系中也很常见。 关于银河系这个奇异天体的大部分了解都来自对其强引力场影响的恒星运动学的研究。 迄今为止，还不存在直接对黑洞成像的可能性，或者更技术地说，对它的事件视界（事件视界）进行成像，事件视界是引力“不归点”，在该点内任何粒子或光子都无法逃离黑洞。 银河系中心区域距离很远，约为8 kpc，因此通过任何直接技术获得超大质量黑洞的高分辨率空间图像都异常困难。 如果能够获得这样的图像，它们将是此类图像中的第一张，并且可以揭示有关黑洞和星系核心动力学的尚未想象的信息。为了解决这个具有挑战性的科学问题，博士。亚利桑那大学的 D. Marrone、东北射电天文台公司的 S. Doeleman 和芝加哥大学的 J. Carlstrom 打算增强在最高无线电频率（亚毫米级，波长）下运行的现有射电望远镜阵列略短于一毫米），并且在一种模式下，由大陆基线分开的望远镜将其数据连贯地结合起来，以实现前所未有的空间分辨率。 通用技术被称为甚长基线干涉测量法（VLBI），所使用的特定射电望远镜阵列被称为事件视界望远镜（EHT），部分是通过美国国家科学基金会先前的奖项开发的。 通过一项新的 NSF 提案，研究人员计划将南极望远镜 (SPT) 添加为 EHT 的新站。 以这种方式添加站（望远镜）可以增强对无线电信号的灵敏度，还可以提高作为成像设备的仪器的空间响应，从而可以由较暗的物体绘制出质量更好的地图。 除了增加一个关键观测站外，该技术还将采用新型、灵敏的双波段毫米波 VLBI 接收器，该接收器针对该项目的需求进行了优化，该接收器将采用为阿塔卡马大型毫米波阵列开发的超导混频器技术（国家射电天文台 (NRAO) 的 ALMA) 项目。 最后，经过验证的 230 GHz 设计将适用于 345 GHz。这项工作的资金由 NSF 天文科学部通过其先进技术和仪器计划提供。