RUI: Probing the Interstellar Medium Using Pulsar Scintillation

脉冲星的闪烁或强度变化可以用来探测类似太阳系大小的星际介质。由于闪烁是由星际气体中电离成分的密度变化的多路径散射引起的，对脉冲星闪烁的详细研究可以获得关于星际气体如何聚集、是否表现出湍流以及密度变化是如何启动和维持的信息。这些问题对于理解我们银河系的动力学，以及其他类似我们的螺旋星系的动力学是至关重要的。在之前的资助期间，丹尼尔·斯泰内布林博士发现，在动态光谱中观察了几十年的交错模式在变换空间中具有更清晰的特征。他的团队现在已经利用主要由阿雷西博射电望远镜获得的脉冲星的高动态范围观测，对这种闪烁弧线现象进行了广泛的研究。利用这一新奖项开展的研究将利用阿雷西博射电望远镜和其他大型望远镜的高灵敏度观测来详细探索这一现象。详细的子结构，包括反转子弧，将被充分探索，并将确定它们的时间尺度和频率行为。这项工作的目标是将对闪烁弧线的详细观察与星际电离介质中湍流气体的物理特征联系起来。这项研究计划将让本科生兴奋地探索一种新现象，并拼凑出一个更大谜题的部分：星际气体的大规模搅动如何产生小尺度湍流，最终以热量的形式消散？通过与斯廷布林博士和他的合作者密切合作，学生们将获得广泛的技术技能，并进一步发展他们独立探索问题的能力。使用世界上最大的射电望远镜的最先进的电子和计算机，学生将获得信心，他们有能力解决大型和复杂的问题。与美国和国外的科学家合作并在会议和出版物上报告他们的工作的机会将增强学生的研究经验，并为他们在研究生培训或技术劳动力中的其他角色做好准备。*

The scintillation, or intensity variation, of pulsars can be used to probe the interstellar medium on size scales similar to that of the solar system. Since scintillation is caused by multi-path scattering off of density variations in the ionized component of the interstellar gas, a detailed study of pulsar scintillation yields information about how the interstellar gas is clumped, whether or not it exhibits turbulence, and how the density variations are initiated and sustained. These questions are central to an understanding of the dynamics of our galaxy and, hence, of other spiral galaxies like ours. During the previous grant period, Dr. Daniel Stinebring discovered that a crisscross pattern that had been noticed for decades in dynamic spectra has a much clearer signature in transform space. His group has now studied this scintillation arc phenomenon extensively, using high dynamic range observations of pulsars, primarily obtained with the Arecibo radio telescope. The research carried out with this new award will explore this phenomenon in detail using high-sensitivity observations from the Arecibo radio telescope and other large telescopes. Detailed substructure, including inverted subarcs, will be explored fully and their timescale and frequency behavior will be determined. The goal of this work is to connect the detailed observations of scintillation arcs with the physical characteristics of turbulent gas in the ionized interstellar medium.This research program will involve undergraduate students in the excitement of exploring a new phenomenon and piecing together parts of a bigger puzzle: how does large scale stirring of the interstellar gas create small scale turbulence which is eventually dissipated as heat? By working closely with Dr. Stinebring and his collaborators, the students will gain a broad range of technical skills as well as further develop their ability to independently explore problems. Using state-of-the-art electronics and computers at the largest radio telescopes in the world, the students will gain confidence in their ability to tackle large and complex problems. Opportunities to collaborate with scientists in the U.S. and abroad and to report their work at conferences and in publications will enhance students research experience and prepare them for graduate training or other roles in the technical workforce.***