Particle Astrophysics with the VERITAS Detector

这项申请是为了支持麦吉尔继续参与VERITAS伽马射线天体物理项目。VERITAS(超高能辐射成像望远镜阵列系统)是世界上使用成像大气切伦科夫技术研究能量大于100GeV的天体物理伽马射线的三个主要探测器之一。它由四个大型望远镜组成，旨在探测高能电子和正电子在高层大气中相互作用时产生的紫外线和蓝色切伦科夫光。这种伽马射线是在超新星遗迹和活动星系核等极端环境中产生的。也可能有伽马射线来自更奇怪的来源，如星系核心中暗物质粒子的湮灭或原始黑洞的蒸发。因此，他们可以提供关于粒子物理的信息，能量超过了地球上的加速器可以探测到的能量。位于亚利桑那州南部的Veritas阵列于2007年完工，并于同年9月开始进行四个望远镜的观测。到目前为止，我们已经探测到了八类40多种天体物理伽马射线源。其中大约一半是新发现的；其余的是确认的。我们利用X射线、光学和射电望远镜以及费米伽马射线空间望远镜的数据参加了多波长活动，费米伽马射线空间望远镜覆盖的伽马射线能量范围略低于VERITAS的敏感区。一种新的陆基全天探测器HAWC的能量略高于VERITAS射程中的探测器，我们已经启动了与它们协调观测的计划。对冰立方中微子天文台和Pierre Auger超高能宇宙线天文台有趣提示的后续研究是我们计划的一部分，与LIGO引力波天文台相关的类似活动即将开始。*Veritas探测器达到并超过了所有设计规格，但我们仍在继续改进。2009年，我们移动了四台望远镜中的一台来优化阵列布局，2012年夏天，我们用新推出的高量子效率型号更换了望远镜相机中的所有光电倍增管，进一步提高了我们的灵敏度。安装了新的触发器，以允许在较低的能量阈值下运行，并将改进的重建和背景抑制技术纳入分析流中。根据前几年的产出，我们预计将迎来一段科学生产率很高的时期，并取得许多令人振奋的新成果。

This application is for funding to support continued McGill participation in the VERITAS gamma-ray astrophysics project. VERITAS (Very Energetic Radiation Imaging Telescope Array System) is one of three major detectors world-wide that study astrophysical gamma rays with energies greater than 100 GeV, using the Imaging Atmospheric Cherenkov Technique. It consists of an array of four large telescopes designed to detect the ultraviolet and blue Cherenkov light emitted by energetic electrons and positrons produced when high-energy gamma rays interact in the upper atmosphere. Such gamma rays are produced in extreme environments such as supernova remnants and active galactic nuclei. There may also be gamma rays which come from more exotic origins such as annihilation of dark-matter particles in the cores of galaxies or from evaporation of primordial black holes. As such, they could provide information about particle physics at energies beyond what can be probed at Earth-bound accelerators. The VERITAS array, located in southern Arizona, was completed in 2007 and began four-telescope observations in September of that year. So far we have detected over 40 sources of astrophysical gamma rays, in eight classes. Approximately half of these are new discoveries; the remainder are confirmations. We have participated in multi-wavelength campaigns with data from X-ray, optical and radio telescopes, as well as the Fermi Gamma-ray Space Telescope which covers the gamma-ray energy range just below that where VERITAS is sensitive. A new ground-based all-sky detector, HAWC, operates at energies slightly higher than those in the VERITAS range and we have started a program of coordinated observations with them. Follow-ups on interesting hints from the IceCube neutrino observatory and the Pierre Auger ultra-high-energy cosmic-ray observatory are part of our program, with similar activities connected to the LIGO gravitational wave observatory about to begin.*** ***The VERITAS detector has met and exceeded all design specifications but we continue to improve it. In 2009 we moved one of the four telescopes to optimize the array layout and in the summer of 2012 we replaced all photomultipliers in the telescope cameras with newly available high-quantum-efficiency models, further increasing our sensitivity. A new trigger has been installed to allow running at lower energy threshold and improved reconstruction and background-rejection techniques have been incorporated into the analysis stream. Based on the output from the previous years we expect a period of high scientific productivity and many exciting new results.**