We report a measurement of the energy spectrum of cosmic rays above $2.5\times {10}^{18}\mathrm{eV}$ based on 215 030 events. New results are presented: at about $1.3\times {10}^{19}\mathrm{eV}$, the spectral index changes from $2.51\pm 0.03(\mathrm{stat})\pm 0.05(\mathrm{syst})$ to $3.05\pm 0.05(\mathrm{stat})\pm 0.10(\mathrm{syst})$, evolving to $5.1\pm 0.3(\mathrm{stat})\pm 0.1(\mathrm{syst})$ beyond $5\times {10}^{19}\mathrm{eV}$, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above $5\times {10}^{18}\mathrm{eV}$ is $[5.66\pm 0.03(\mathrm{stat})\pm 1.40(\mathrm{syst})]\times {10}^{53}\mathrm{erg}{\mathrm{Mpc}}^{-3}$.

中文翻译：

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2.5×1018eV以上宇宙射线能谱的特征利用皮埃尔·奥格天文台

我们报告了以上宇宙射线能谱的测量 $2.5\times {10}^{\mathrm{18岁}}\mathrm{电子伏特}$基于215030个事件。提出了新结果：大约在$1.3\times {10}^{19}\mathrm{电子伏特}$，光谱指数从 $2.51\pm 0.03（\mathrm{统计}）\pm 0.05（\mathrm{系统}）$ 至 $3.05\pm 0.05（\mathrm{统计}）\pm 0.10（\mathrm{系统}）$，发展为 $5.1\pm 0.3（\mathrm{统计}）\pm 0.1（\mathrm{系统}）$ 超越 $5\times {10}^{19}\mathrm{电子伏特}$，虽然在可访问范围内看不到光谱特征对磁偏角的显着依赖。光谱的这些特征可以在与能量相关的质量组成的模型中重现。上方宇宙射线的能量密度$5\times {10}^{\mathrm{18岁}}\mathrm{电子伏特}$ 是 $[5.66\pm 0.03（\mathrm{统计}）\pm 1.40（\mathrm{系统}）]\times {10}^{53}\mathrm{尔格}{\mathrm{Mpc}}^{-3}$。