High-redshift blazars are valuable tools to study the early Universe. So far only a handful of $γ$-ray blazars have been found at redshifts above 3. $γ$-ray signals are detected in the direction of PMN J2219-2719 ($z=3.63$) and PMN J2321-0827 ($z=3.16$) by analyzing the 10-year $Fermi$-LAT Pass 8 data. PMN J2219-2719 is not distinguished from the background in the global analysis. During the 5-month epoch, the TS value is 47.8 and the flux is more than 10 times of the 10-year averaged flux. In addition, the angular distance between the $γ$-ray position and the radio position of PMN J2219-2719 is only ${0.04}^{\circ}$. Moreover, the $γ$-ray and infrared light curves of long time scale are very similar, which support the association between the $γ$-ray source and PMN J2219-2719. The global analysis of PMN J2321-0827 suggest a new $γ$-ray source, during the flare phase, the TS value is 61.4 and the $γ$-ray flux increased significantly. The association probability suggests that PMN J2321-0827 may be the counterpart of the new $γ$-ray source. In the future, the number of high-redshift $γ$-ray sources will increase by combining $Fermi$-LAT and the upcoming Large Synoptic Survey Telescope.
Identification of a Large-Scale Diffuse Gamma-Ray Structure in the Southern Galactic Hemisphere
School of Astronomy and Space Science, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）；Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台暗物质与空间天文重点实验室）
A new air shower array in the Southern Hemisphere looking for the origins of Cosmic rays: the ALPACA experiment
Institute for Cosmic Ray Research, University of Tokyo（东京大学宇宙射线研究所）；Departamento de Física, CUCEI, Universidad de Guadalajara（瓜达拉哈拉大学CUCEI物理系）；College of Engineering, Chubu University（中部大学工程学院）；Department of Science and Technology, Shinshu University（信州大学科学技术部）；Faculty of Engineering, Kanagawa University（神奈川大学工学院）；Faculty of Education, Utsunomiya University（宇都宫大学教育学部）；Departamento de Tecnologías de la Información, CUCEA, Universidad de Guadalajara（瓜达拉哈拉大学CUCEA信息技术系）；Faculty of Engineering, Yokohama National University（横滨国立大学工学院）；Department of Physics, Shinshu University（信州大学物理学部）
Gamma-ray Astronomy with Muons: Sensitivity of IceCube to PeVatrons in the Southern Sky
北半球TeV伽马射线观测站，如Milagro和Tibet AS $γ$，通过发现以前未被识别的源，可能是PeVatron产生的宇宙射线谱中高达“膝盖”的宇宙射线，证明了全天空仪器的重要性。我们评估冰立方的潜力，以确定类似的源在南部天空中的详细分析方法，以确定通量的μ子从TeV的伽马射线阵雨。我们将这种方法应用于已知的伽马射线源，如超新星遗迹。我们发现，与米拉格罗类似，对于通量强于几个10^{-11}粒子TeV^{-1} cm^{-2} s^{-1}的点状PeVatron，在10年内就有可能探测到。
