The ultra-high-energy (UHE) Galactic diffuse gamma-ray emission holds important information on the propagation of cosmic rays in the Galaxy. However, its measurements suffer from a contamination from unresolved sources whose contribution remains unclear. In this Letter, we propose a novel data-driven estimate of the contribution of unresolved pulsar wind nebulae and TeV halos based on the information present in the Australia Telescope National Facility and the LHAASO catalogs. We find that in the inner Galaxy, this contribution is limited to ∼38% ± 10% of the diffuse flux measured by LHAASO at ∼20 TeV in the case where all sources associated to pulsars contribute as unresolved sources, and this fraction drops to less than 21% ± 6% above 100 TeV. In the outer Galaxy, this contribution is always subdominant. In particular, it reaches at most ∼18% ± 2% at 10 TeV and is less than ∼7% ± 1% above ∼25 TeV. We conclude that the UHE Galactic diffuse gamma-ray emission cannot be dominated by unresolved pulsar sources above a few tens of TeV.

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关于未分辨脉冲星对超高能银河漫射伽马射线发射的贡献


超高能 （UHE） 银河漫射伽马射线发射包含有关宇宙射线在银河系中传播的重要信息。然而，它的测量受到来自未解析来源的污染，其影响尚不清楚。在这封信中，我们根据澳大利亚望远镜国家设施和 LHAASO 星表中提供的信息，对未分辨的脉冲星风星云和 TeV 晕的贡献提出了一种新的数据驱动估计。我们发现，在银河系内部，这种贡献仅限于 LHAASO 在 ∼20 TeV 时测量的漫散通量的 ∼38% ± 10%，在这种情况下，与脉冲星相关的所有源都是未分辨的源，并且这个比例下降到低于 21% ± 100 TeV 以上的 6%。在外星系中，这种贡献总是次主导的。特别是，它在 10 TeV 时最高达到 ∼18% ± 2%，在 ∼25 TeV 时低于 ∼7% ± 1%。我们得出结论，UHE 银河漫射伽马射线发射不能由几十 TeV 以上的未分辨脉冲星源主导。