标题： 银河系外暗物质湮灭的伽马射线信号：基于功率谱的计算 显示英文标题

标题： Extragalactic gamma-ray signal from Dark Matter annihilation: a power spectrum based computation

摘要： 我们重新审视了宇宙学暗物质湮灭产生的星系外伽马射线信号的计算。 该信号的预测因对小尺度上暗物质分布的致密性描述不同而具有明显的模型依赖性，这导致其相对于平滑分布的情况有所增强。 我们展示了如何通过非线性功率谱直接计算这一“通量乘数”，这种方法在概念上更为简单，并可能缓解一些问题，例如外推问题。 事实上，构建功率谱的非常简单的解析方法可以得到与流行的晕模型预期相似的结果，并提供了误差的直接替代估计。 对于这个特定的应用，还可以避免识别（通常依赖于文献的）进入晕模型的概念，以比较不同的模拟。 显示英文摘要

摘要： We revisit the computation of the extragalactic gamma-ray signal from cosmological dark matter annihilations. The prediction of this signal is notoriously model dependent, due to different descriptions of the clumpiness of the dark matter distribution at small scales, responsible for an enhancement with respect to the smoothly distributed case. We show how a direct computation of this "flux multiplier" in terms of the nonlinear power spectrum offers a conceptually simpler approach and may ease some problems, such as the extrapolation issue. In fact very simple analytical recipes to construct the power spectrum yield results similar to the popular Halo Model expectations, with a straightforward alternative estimate of errors. For this specific application, one also obviates to the need of identifying (often literature-dependent) concepts entering the Halo Model, to compare different simulations.