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是超越粒子物理学和宇宙学标准模型的新物理学的标志。在伽马射线光谱的低端，伽马射线的通量足以用大气层上方轨道上的卫星探测到它们。对大约100 GeV以上的高能（VHE）伽马射线进行研究，需要数千平方米的收集面积的探测器，而这些探测器只能建在地面上。这些地面设备通过探测伽马射线在大气中相互作用时产生的二次粒子阵雨来间接探测伽马射线。该合同将为UCSC小组提供资金，使用位于亚利桑那州南部的VERITAS（非常高能辐射成像望远镜阵列系统）成像切伦科夫望远镜阵列来研究VHE伽马射线。他们计划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（GRB）和活动星系核（AGN）。grb如何工作的细节以及它们在其他高能现象中所起的作用（例如，它们是最高能量宇宙射线的加速器吗？）仍在探索中。了解它们是否能够在一般情况下，在特定情况下，或者根本没有能力产生VHE伽马射线，将限制GRB模型和爆发环境的性质。同样，测量AGN发射的VHE伽玛射线探测AGN喷流的特性，提供关于加速粒子和加速如何工作的关键信息。这项工作具有广泛的影响，特别是在教育和技术基础设施领域。研究生和本科生，包括来自代表性不足群体的学生，在研究工作中发挥着重要作用。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。他们将与VERITAS的合作者一起开发伽玛射线天体物理学展览，用于科学博物馆和天文台游客中心。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. At the low end of the gamma-ray spectrum, the flux of gamma rays is sufficient to detect them with satellites in orbit above the atmosphere. Studies with very-high-energy (VHE) gamma rays, above about 100 GeV, require detectors with thousands of square meters of collection area, which can only be built on the ground. These ground-based devices detect gamma rays indirectly, by detecting the shower of secondary particles produced when a gamma ray interacts in the atmosphere. This award will provide funds for the UCSC group to use the VERITAS (Very Energetic Radiation Imaging Telescope Array System) imaging Cherenkov telescope array in southern Arizona to study VHE gamma rays. They plan to explore the extreme behavior of the two most powerful known classes of gamma-ray source: gamma-ray bursts (GRB) and active galactic nuclei (AGN). The details of how GRBs work and the role they play in other high energy phenomena (for example, are they the accelerators of the highest energy cosmic rays?) are still being explored. Learning whether they are capable of creating VHE gamma rays in general, in particular circumstances, or not at all, will constrain GRB models and properties of the burst environment. Similarly, measurements of the VHE gamma-ray emission from AGN probe properties of the AGN jet, providing crucial information about the particles being accelerated and how the acceleration works. This work has wide-ranging broader impacts, particularly in the areas of education and technological infrastructure. Graduate and undergraduate students, including students from underrepresented groups, play an important part in the research effort. The researchers interact with the California State University to foster undergraduate interest in research and graduate education. They will work with their VERITAS collaborators to develop exhibits on gamma-ray astrophysics for use at science museums and observatory visitors' centers. 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.