Numerous particle models for the cosmological dark matter feature a pair-annihilation rate that scales with powers of the relative velocity between the annihilating particles. As a result, the annihilation rate in the central regions of a dark matter halo can be significantly lower than at the halo’s periphery for particular ambient gravitational potentials. While this might be offset by an increasing dark matter pair number density in the inner halo, it raises the question; what angular region for dark matter models with velocity-suppressed annihilation rates optimizes the signal to noise ratio? Here, we consider simplified background models for galactic and extragalactic targets and demonstrate that the optimal observing strategy varies greatly case by case. Generally, a bright central source warrants an annular region of interest, while a flatter background warrants as large as possible an angular region, possibly including the central regions.

中文翻译：

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速度抑制暗物质湮灭的最佳观测策略

宇宙学暗物质的许多粒子模型都具有成对湮灭率，该比率与湮灭粒子之间的相对速度的幂成比例。因此，对于特定的环境引力势，暗物质晕中心区域的湮灭率可能明显低于晕外围。虽然这可能会被内晕中不断增加的暗物质对数密度所抵消，但它提出了一个问题；具有速度抑制湮灭率的暗物质模型的哪个角区域优化了信噪比？在这里，我们考虑了银河和河外目标的简化背景模型，并证明了最佳观测策略因情况而异。一般来说，一个明亮的中心源保证一个感兴趣的环形区域，