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arXiv 2111.12366astro-ph.HE
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原始俄歇和TA表面探测器和附近星系最新数据中的UHECR到达方向

UHECR arrival directions in the latest data from the original Auger and TA surface detectors and nearby galaxies

Armando di Matteo, Luis Anchordoqui, Teresa Bister, Jonathan Biteau, Lorenzo Caccianiga, Rogério de Almeida, Olivier Deligny, Ugo Giaccari, Diego Harari, Jihyun… 展开作者

Armando di Matteo, Luis Anchordoqui, Teresa Bister, Jonathan Biteau, Lorenzo Caccianiga, Rogério de Almeida, Olivier Deligny, Ugo Giaccari, Diego Harari, Jihyun Kim, Mikhail Kuznetsov, Ioana Mariş, Grigory Rubtsov, Peter Tinyakov, Sergey Troitsky, Federico Urban

摘要:

除了$6 \times (E/10~\mathrm{EeV})$ %量级的偶极矩外,超高能宇宙射线到达方向的分布几乎是各向同性的。尽管如此,在最高能量下,随着传播视界内可能的候选源数量和磁偏转都缩小,可能会出现较小尺度的各向异性。另一方面,通量抑制减少了可用于搜索这种各向异性的统计。在这项工作中,我们考虑了两个不同的候选源列表:附近星暴星系的样本和追踪$250~\mathrm{Mpc}$内恒星质量的2 MRS目录。我们结合表面探测器收集的数据,在皮埃尔俄歇天文台,直到2020年和望远镜阵列,直到2019年,并使用它们来测试模型,其中UHECR包括一个各向同性的背景和前景起源于候选源和随机偏转的磁场。这些模型的自由参数是能量阈值、信号分数和搜索角尺度。我们发现$11.8\%_{-3.1\%}^{+5.0\%}$的宇宙射线的到达方向与$E \ge 38~\mathrm{EeV}$俄歇或$E \gtrsim 49~\mathrm{EeV}$ TA和附近的星暴星系的位置上的${15.5^\circ}_{-3.2^\circ}^{+5.3^\circ}$角尺度上的相关性,与$4.2σ$后审判的意义,以及较弱的相关性与整体星系分布。

英文摘要:

The distribution of ultra-high-energy cosmic-ray arrival directions appears to be nearly isotropic except for a dipole moment of order $6 \times (E/10~\mathrm{EeV})$ per cent. Nonetheless, at the highest energies, as the number of possible candidate sources within the propagation horizon and the magnetic deflections both shrink, smaller-scale anisotropies might be expected to emerge. On the other hand, the flux suppression reduces the statistics available for searching for such anisotropies. In this work, we consider two different lists of candidate sources: a sample of nearby starburst galaxies and the 2MRS catalog tracing stellar mass within $250~\mathrm{Mpc}$. We combine surface-detector data collected at the Pierre Auger Observatory until 2020 and the Telescope Array until 2019, and use them to test models in which UHECRs comprise an isotropic background and a foreground originating from the candidate sources and randomly deflected by magnetic fields. The free parameters of these models are the energy threshold, the signal fraction, and the search angular scale. We find a correlation between the arrival directions of $11.8\%_{-3.1\%}^{+5.0\%}$ of cosmic rays detected with $E \ge 38~\mathrm{EeV}$ by Auger or with $E \gtrsim 49~\mathrm{EeV}$ by TA and the position of nearby starburst galaxies on a ${15.5^\circ}_{-3.2^\circ}^{+5.3^\circ}$ angular scale, with a $4.2σ$ post-trial significance, as well as a weaker correlation with the overall galaxy distribution.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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