The Construction of a Pulsar Interstellar Medium Array Detector

星际空间充满了丰富的气体和尘埃介质。大多数天文学家在星际介质（ISM）中拍摄大型结构的图像。然而，对脉冲星穿过ISM的无线电波的观测允许进入更小的尺度。这些脉冲星在银河系的活跃环境中扮演着探测器的角色。天文学家利用脉冲星来了解ISM中的湍流，识别云和细丝，甚至了解来自太阳的粒子流风。研究人员将结合世界各地许多望远镜对数百颗脉冲星的观测结果。这些将被组合成一个星系大小的探测器，被称为“脉冲星ISM阵列”。这项工作将把世界各地的脉冲星天文学家与许多其他社区联系起来，以创建我们动态星系的详细图片。调查人员还将建立教室实验室和外展示范。这将使学生和公众了解ISM的复杂现象。研究人员将构建一个“脉冲星ISM阵列”（PISMA），类似于用于低频引力波研究的脉冲星定时阵列（PTA）。由于所有脉冲星的发射都被ISM分散，所以所有脉冲星都可以为PISMA做出贡献，而不仅仅是PTA实验中使用的超精密脉冲星。结合广泛的观测数据，包括但不限于脉冲星色散测量、闪烁参数、通量密度变化、二次光谱，以及非脉冲星观测数据，如h - α巡天的天图，PISMA将为理解湍流能量从千帕差距到亚天文单位尺度的转移过程提供关键见解；致密等离子体结构和超大密度的形成、形态和种群；以及脉冲星周围的极端环境条件。推进对这些领域的理解也将有利于更广泛的天文学界研究快速射电暴和星系外瞬变、空间天气和射电类星体的日内变化，并为迄今为止最复杂的银河系电子密度图提供输入。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Interstellar space is filled with a rich medium of gas and dust. Most astronomers take images of large structures in the interstellar medium (ISM). However, observations of radio waves from pulsars traveling through the ISM allow access to much smaller scales. These pulsars act as probes within the Galaxy's active environments. Astronomers use pulsars to understand turbulence in the ISM, identify clouds and filaments, and even understand the wind of particles streaming from the Sun. The investigators will combine observations of hundreds of pulsars by many telescopes around the world. These will be combined to create Galaxy-sized detector known as a "Pulsar ISM Array." This work will connect pulsar astronomers around the world with many other communities to create a detailed picture of our dynamic Galaxy. The investigators will also build classroom laboratory and outreach demonstrations. These will engage students and the public in understanding the complex phenomena of the ISM.The investigators will construct a "Pulsar ISM Array" (PISMA) analogous to a pulsar timing array (PTA) used in the study of low-frequency gravitational waves. Since all pulsar emission is dispersed by the ISM, all pulsars can contribute to the PISMA and not just the ultra-precise ones used in PTA experiments. In combining a wide-range of observables, including but not limited to pulsar dispersion measures, scintillation parameters, flux-density variations, secondary spectra, along with non-pulsar observables such as sky maps from H-alpha surveys, the PISMA will provide key insights into understanding the processes that govern the transfer of turbulent energy from kiloparsec to sub-AU scales; the formation, morphology, and population of compact plasma structures and larger-scale over-densities; and the extreme environmental conditions around pulsars themselves. Advancing understanding in these areas will also benefit understanding in the broader astronomical communities researching Fast Radio Bursts and extragalactic transients, space weather, and intraday variability of radio quasars, and provide input into the most sophisticated Galactic electron density maps yet created.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.