RUI: WoU-MMA: From Origin to Observation: Understanding Extragalactic Gamma-rays from Blazars

耀变体是观测到的局部宇宙中最极端的物体之一，当从超大质量黑洞发出的喷流与地球的大致方向对齐时就会发生。 作为预期的最高能量宇宙射线的天体物理加速器，观测到的极高能伽马射线与这些物体一致，并提供了研究基本过程的手段。 该奖项支持加州州立大学东湾分校（CSUEB）的科学家利用位于亚利桑那州图森市南部的VERITAS望远镜对VHE伽马射线的观测，研究当地宇宙中最具活力的星系的行为。 该计划为CSUEB的本科生提供了领先粒子天体物理学研究的实践经验的机会。 利用对极高能星系的伽马射线观测，学生们将研究高能光子从星系到地球旅行时可能发生的不同过程，并将他们所学的知识应用于地球和高能星系之间宇宙的大尺度结构。 与此相关的是，该方案将推进对当前和未来甚高能量辐射伽马射线观测站感兴趣的天体物理事件进行有针对性的实时跟踪。由耀变体喷射出的极高能量光子和超高能宇宙射线（能量1 PeV）在穿越从源到观测者的河外距离时有可能引发级联过程。由于这些相互作用，观测到的伽马射线通量并不是严格意义上的源辐射。相反，观测到的伽马射线通量可能是被吸收的固有伽马射线通量（初级辐射）和上散射伽马射线（次级辐射）的组合，这些伽马射线是沿着沿着河外路径的级联过程产生的。由级联发射产生的伽马射线通量中继续沿着原始视线传播的部分取决于星系际磁场的大小。提出的产生大规模磁场的天体物理机制预测，在较低的综合质量密度区域（也称为空洞）内，磁通量很小。 研究伽马射线发射星系相对于宇宙空洞的位置可以提供关于空洞内部磁场强度的见解。该项目推进了NSF宇宙大创意窗口的目标。该奖项反映了NSF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。

Blazars, one of the most extreme objects in the observed local Universe, occur when the jet emitted from a supermassive black hole is aligned in the general direction of the Earth. An anticipated astrophysical accelerator for cosmic rays at the highest energies, very-high-energy (VHE) gamma-rays are observed coincident with these objects and provide a means to study the underlying processes. This award supports scientists at the California State University - East Bay (CSUEB) to utilize observations of VHE gamma-rays with the VERITAS telescope, located south of Tucson, Arizona, to study the behavior of the most energetic galaxies within the local Universe. The program provides the opportunity for hands-on experience in leading particle astrophysics research for undergraduates at CSUEB. Using gamma-ray observations of extremely energetic galaxies, the students will study the different processes that can occur to high energy photons as they travel from the galaxy to the Earth and apply what they learn to the large-scale structure of the Universe between Earth and the energetic galaxy. Relatedly, the program will advance target-of-opportunity real-time follow-ups of astrophysical events of interest for current and future VHE gamma-ray observatories. Very high energy photons and ultra-high-energy cosmic-rays (Energy 1 PeV) ejected by a blazar have the potential to initiate a cascade process as they traverse the extragalactic distance from source to observer. Due to these interactions, the observed gamma-ray flux is not strictly that which is emitted at the source. Instead, the observed flux may be a combination of the absorbed intrinsic gamma-ray flux (primary emission) and the up-scattered gamma-rays that result from the cascade process along the extragalactic path (secondary emission). The portion of the gamma-ray flux resulting from cascade emission which continues to travel along the original line of sight depends on the magnitude of the intergalactic magnetic field. The proposed astrophysical mechanisms for generating large-scale magnetic fields predict little magnetic flux inside regions of lower integrated mass density, also known as voids. Studying the location of gamma-ray emitting galaxies with respect to cosmic voids can provide insight on the strength of the magnetic field inside of voids. This project advances the goals of the NSF Windows on the Universe Big Idea.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.