Astrophysics with Very High Energy Gamma Rays

高能伽马射线被用来研究宇宙中最极端的物体，如脉冲星、活跃星系中心的黑洞和伽马射线暴。宇宙伽马射线也可以成为超越粒子物理学和宇宙学标准模型的新物理学的标志。研究大约100千兆电子伏特（GeV）以上的高能伽马射线，需要有数千平方米收集面积的地面探测器。这项研究将使用位于亚利桑那州南部的VERITAS成像切伦科夫望远镜阵列来研究能量大于100 GeV的伽马射线。VERITAS的灵敏度比在此能量范围内工作的上一代仪器好一个数量级以上，并且刚刚通过大幅升级进一步改进。有了这个奖项，加州大学圣克鲁斯分校的研究小组将使用VERITAS来探索两种已知最强大的伽玛射线源的极端行为：伽玛射线暴和活动星系核。伽玛射线爆发的详细机制及其在其他高能现象中所起的作用仍在探索中。了解它们是否能够产生高能伽马射线将限制伽马射线暴模型和爆发环境的性质。同样，对活动星系核发射的高能伽玛射线的测量可以探测喷流的特性，提供关于粒子加速和加速如何工作的关键信息。来自整个电磁波谱的数据将被收集起来，并用于组装最完整的高能伽马射线行为图。这些数据还将用于研究与河外背景光碰撞产生的伽马射线吸收，这是一个测试恒星形成和星系演化的宇宙学模型的过程。更广泛的影响：研究生和本科生在这项研究工作中发挥重要作用。研究经验也将提供给有抱负的科学教师在Cal教学计划和在职教师通过一个新的利克天文台教师研究所。研究人员与加州州立大学进行互动，以培养本科生对研究和研究生教育的兴趣。VERITAS的数据与其他波长的数据之间存在重要的相互作用，特别是来自Swift和Fermi等卫星任务的x射线和低能量伽马射线数据。将这两种数据结合使用比单独使用任何一种数据都能学到更多的东西。

High-energy gamma-rays are used to study the most extreme objects in the Universe, such as pulsars, black holes at the center of active galaxies, and gamma-ray bursts. Cosmic gamma-rays can also be signatures for new physics beyond the standard models of particle physics and cosmology. Studies with very-high-energy gamma rays, above about 100 gigaelectron volt (GeV), require ground-based detectors with thousands of square meters of collection area. This research will use the VERITAS imaging Cherenkov telescope array in southern Arizona to study gamma-rays with energy greater than about 100 GeV. The sensitivity of VERITAS is more than an order of magnitude better than previous generation instruments operating in this energy range and has just been improved further by a substantial upgrade. With this award the University of California - Santa Cruz group will use VERITAS to explore the extreme behavior of the two most powerful known classes of gamma-ray source: gamma-ray bursts and active galactic nuclei. The detail mechanisms of gamma-ray bursts and the role they play in other high-energy phenomena are still being explored. Learning whether they are capable of creating very-high-energy gamma-rays will constrain gamma-ray burst models and properties of the burst environment. Similarly, measurements of the very-high-energy gamma-ray emission from active galactic nuclei probe properties of the jets, providing crucial information about the particles being accelerated and how the acceleration works. Data from across the electromagnetic spectrum will be gathered and used to assemble the most complete possible picture of very high-energy gamma-ray behavior. These data will also be used to study gamma-ray absorption by collisions with the extragalactic background light, a process that tests cosmological models of star formation and galaxy evolution.Broader Impact: Graduate and undergraduate students play an important part in this research effort. Research experiences will also be made available to aspiring science teachers in the Cal Teach program and in-service teachers through a new Lick Observatory Teachers Institute. The researchers interact with the California State University to foster undergraduate interest in research and graduate education. There is an important interplay between the VERITAS data and data from other wavelengths, particularly X-ray and lower energy gamma-ray data from satellite missions such as Swift and Fermi. More can be learned from both types of data used together than from either alone.