MRI: Acquisition of Stable Hydrogen Maser Frequency Standards for Millimeter/Submillimeter VLBI Observations of a Black Hole Event Horizon

MRI：获取稳定的氢脉泽频率标准，用于黑洞事件视界的毫米/亚毫米 VLBI 观测

• 批准号: 1337663
• 负责人: Sheperd Doeleman
• 金额: $ 41.06万
• 依托单位: Smithsonian Institution Astrophysical Observatory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1337663&HistoricalAwards=false
• 关键词: MRI; Acquisition; Stable; Hydrogen; Maser

Black holes are perhaps the most exotic and enigmatic objects in the universe. Predicted by Einstein's theory of General Relativity and widely accepted as products of certain examples of massive single-star and binary-star evolution, the most dramatic cases are the "supermassive" black holes found in the centers of essentially all galaxies. Here, accretion has amassed as much matter as exists in 20 billion stars into extraordinarily tiny volumes. Our Galaxy hosts a comparatively modest example, with some 4 million solar masses packed inside a region no larger than Uranus' orbit around the Sun.Until now, the tiny sizes of black holes coupled with their vast distances have permitted us to view only the gravitational effects of black holes on surrounding stars and gas. However, Dr. S. Doeleman (Smithsonian Astrophysical Observatory) and collaborators are employing the Very Large Baseline Interferometry (VLBI) technique pioneered by radio astronomers to combine signals from several telescopes scattered around the Earth with the goal of imaging the radio emission from just outside a black hole's point of no return - the so-called Schwarzschild radius where the last light emitted by matter flowing into the hole can escape and reach an outside observer.To effectively combine the signals from widely separated telescopes, each signal must be time-stamped with an extremely precise local reference signal. This proposal seeks funds to acquire ultra-stable frequency references for global VLBI observations at mm-wavelengths aimed at obtaining unprecedented views of the immediate environs of the supermassive black hole at the center of our Milky Way, and possibly also of the much more massive hole that lurks at the center of the nearby giant galaxy M87. Fortunately, such time standards have been developed using hydrogen maser oscillators for applications in geodesy and navigation, and therefore are reasonably affordable and extremely reliable. Funding for the acquisition of time standards for the global VLBI network is being provided by NSF's Division of Astronomical Sciences through its participation in the Major Research Instrumentation program.

黑洞可能是宇宙中最异国情调和最神秘的对象。 由爱因斯坦（Einstein）的一般相对论理论预测，并被广泛接受为某些大规模单星和二进制星变化实例的产物，最引人注目的情况是在本质上所有星系中的中心中发现的“超质量”黑洞。 在这里，积聚已经积累了与20亿颗恒星中存在的物质一样多的物质。 我们的银河系举办了一个相对较小的例子，大约400万个太阳能堆积在不超过太阳周围的天王星轨道的区域内。直到现在，直到现在，黑洞的尺寸很小，距离它们的距离很小，使我们只能看到黑孔对周围恒星和气体的重力。 However, Dr. S. Doeleman (Smithsonian Astrophysical Observatory) and collaborators are employing the Very Large Baseline Interferometry (VLBI) technique pioneered by radio astronomers to combine signals from several telescopes scattered around the Earth with the goal of imaging the radio emission from just outside a black hole's point of no return - the so-called Schwarzschild radius where the last light emitted by matter flowing into the hole可以逃脱并到达外部观察者。为了有效地结合广泛分开的望远镜的信号，每个信号都必须用极为精确的局部参考信号来踩踏。 该提议寻求资金以获得全球VLBI观察的超稳定频率参考，旨在获得我们银河系中心的超级大质量黑洞的前所未有的观点，可能还可以在我们近距离Galaxy Galaxy M87附近的孔中心，也可能是更大的孔中心。 幸运的是，这种时间标准是使用氢maser振荡器在地球和导航中应用的，因此相当实惠且非常可靠。 NSF的天文科学部通过参与主要的研究仪器计划提供了为全球VLBI网络获得时间标准的资金。