Mapping the Complete Velocity Field of Extragalactic Jets from sub-parsec to kiloparsec Scales

绘制从亚秒差距到千秒差距尺度的河外喷流的完整速度场

• 批准号: 1814949
• 负责人: Eileen Meyer
• 金额: $ 29.91万
• 依托单位: University of Maryland Baltimore County
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1814949&HistoricalAwards=false
• 关键词: Mapping; Complete; Velocity; Field; Extragalactic

Part 1We now know that essentially all massive galaxies have a super-massive black hole (a million to billion times more massive than the sun) at their centers. Actively growing black holes, also known as active galactic nuclei, are some of the greatest 'recyclers' of matter and energy in the Universe. These accreting black holes are on the scale of our solar system, but have been observed to drive outflows of hot (ionized) gas, known as jets, reaching distances of up to a few million light years (equivalent to typical galaxy separations). These jets have a major impact on both their host galaxies and the clusters of galaxies in which they reside. However, it is still unclear how much energy these jets carry, how they are physically launched from the black hole, and how particles comprising the gas are accelerated to very high energies very far from the black hole engine. The goal of this project is to utilize over 30 years of archival radio imaging with NSF facilities along with new observations, to make the first-ever large compilation of time-lapse observations of dozens of jets over a much larger range of scales than ever before: from very close to the black hole (a few light years) to thousands or millions of light years. Because these jets are moving at nearly the speed of light, we can observe the movement of the gas within the jet on several-year timescales - work that is possible for a large number of jets now that extensive radio archives cover several decades. Mapping the velocity structure of jets will allow us to finally investigate the nature of bright 'knots' in the jet flow, probing regimes of extreme particle acceleration, and to calculate the total energy carried by jets in to the galactic and extra-galactic environment. This is not only critical for understanding the jet phenomenon itself, but will also allow us to improve large-scale computer models of how to Universe was built up over time.Part 2A major open question in Astronomy is the nature of the bipolar jets of relativistic, ionized plasma seen to emanate from a subset of super-massive black holes at the centers of galaxies. An important tool that has been developed over the last two decades is the use of proper motions (motions on the sky) to track the movement of plasma within these jets, both with Very Long Baseline Interferometry (VLBI) and more compact interferometers like the Very Large Array (VLA). Because the plasma in these jets is relativistic (moving very close to the speed of light) and moving with a small angle to our line-of-sight, the motion of features in the jet flow can appear super-luminal (faster than light). A map of the velocity 'field' of a jet, from parsec scales (close to the black hole) to hundreds or thousands of parsecs (outside the host galaxy) is a very important constraint on jet models, showing exactly how gas is accelerated and deposits energy into the environment. Further, measurements of superluminal speeds allow us to constrain intrinsic properties of jets that are very difficult to determine through any other means (including theoretical modeling, due to degeneracies). In this proposal, we aim to dramatically increase the number of extragalactic jets with measured proper motions on the kiloparsec scale, primarily through the use of the VLA archives. Along with complimentary work using the VLBA, the overall goal is to build the first catalog of jets with velocity fields mapped from the scale of the black hole environment to the final terminus of the jet as it impacts the intergalactic medium. These goals will be accomplished by using both standard interferometric imaging techniques and a recently developed wavelet decomposition code. The science questions addressed by this work include the physical nature of the bright 'knot' structures in the jets, the origin of the anomalously high X-ray fluxes from these knots, the connection between morphological type and jet energetics, and the impact of jets on their environment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

第1部分我们现在知道，所有巨大的星系基本上都有一个超级质量的黑洞（比太阳高出一百万到亿倍）。积极生长的黑洞，也称为活性银河核，是宇宙中物质和能量的一些最大的“回收者”。这些积聚的黑洞在我们的太阳系的规模上，但已经观察到可以驱动热（电离）气体的流出，称为喷气机，达到了多达几百万光年的距离（相当于典型的星系间隔）。这些喷气机对他们的宿主星系和居住的星系簇都有重大影响。但是，目前尚不清楚这些喷气机携带的能量，如何从黑洞物理发射，以及如何将包含气体的颗粒加速到距离黑洞发动机非常高的能量。该项目的目的是使用NSF设施以及新的观察结果利用30年来的档案无线电成像，以使有史以来首次大规模汇编数十个尺度上的数十个喷气式飞机的时间比以往任何时候都比以往更大：从非常接近黑洞（几年）或数百万的光明年来。由于这些喷气机几乎以光速移动，因此我们可以在几年的时间尺度上观察到气体在喷气机内的运动 - 对于大量喷气式飞机来说，这是可能的工作，因为广泛的无线电档案涵盖了几十年。映射喷气机的速度结构将使我们能够最终研究射流流中明亮的“结”的性质，探测极端颗粒加速度的探测机制，并计算喷气机在银河系和半乳层面环境中携带的总能量。这不仅对于理解喷气现象本身至关重要，而且还将使我们能够改善大规模的计算机模型，该模型随着时间的流逝而建立的宇宙如何建立。第2A天文学中的主要开放问题是相对论，离子化等离子体的双极喷射的性质，这些血浆被视为从Galaxies的Centerers of Centerers of Centerers of Centerers of Centerers of Centerers of Super-Assive Black holes的子集。 在过去二十年中开发的一个重要工具是使用适当的运动（天空上的运动）来跟踪这些喷气机内血浆的运动，既有基线干涉率很长（VLBI），并且更紧凑的干涉仪（例如非常大的阵列（VLA））。 因为这些喷气机中的血浆是相对论的（非常接近光速的移动），并且与我们的视线距离小角度移动，所以射流流中特征的运动可能会显得超亮（比光快）。 从PARSEC尺度（接近黑洞）到数百或数千个PARSEC（主机星系之外）的速度“场”图是对喷射模型的一个非常重要的限制，表明气体如何加速并将能量沉积到环境中。此外，测量超光速使我们能够限制喷气机的内在特性，这些特性很难通过任何其他方法（包括理论建模，由于退化性）来确定。在此提案中，我们旨在通过基本上使用VLA档案的使用，并以kiloparsec尺度上的适当运动来大大增加静脉外喷射的数量。除了使用VLBA的免费工作外，总体目标是构建从黑洞环境的尺度映射到射流到射流的最终末端的第一个喷气机目录，因为它影响了层间介质。 这些目标将通过使用标准的干涉成像技术和最近开发的小波分解代码来实现。这项工作提出的科学问题包括喷气机中明亮的“结”结构的物理性质，这些结的异常高X射线通量的起源，形态类型和喷气能量学之间的联系以及喷气机对环境的影响。该奖项通过评估了NSF的法定任务，反映了对构成的构成构成的支持，并反映了构成构成的依据。