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arXiv 2106.10399astro-ph.COhep-ph
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用暗晕湮灭信号约束暗物质微观物理

Constraining Dark Matter Microphysics with the Annihilation Signal from Subhalos

Jack Runburg, Eric J. Baxter, Jason Kumar

摘要:

在冷暗物质的情况下,银河系的暗物质晕中充满了大量较小的次晕。先前的工作已经表明,暗晕中的暗物质湮灭可以在伽马射线光子计数概率分布函数(PDF)中产生独特的非泊松信号。在这里,我们表明,伽马射线PDF还携带有关的速度依赖的暗物质湮灭截面的信息。在计算了假设$s$波和Sommerdom增强湮灭的PDF后,我们进行了模拟数据分析,以说明当前和未来的观测如何约束暗物质湮灭的微观物理。我们发现,与目前的费米数据,并假设暗物质湮灭截面大致在当前的界限从湮灭矮球状星系的极限,人们可以潜在地区分非泊松波动预期从暗物质湮灭在subhalos从泊松源,以及从暗物质模型与一个不正确的速度依赖。我们将探讨这些结果对天体物理背景建模的假设有多强。我们还指出了一个四参数的退化之间的速度依赖性的暗物质湮灭,最小晕质量,幂律指数的晕质量函数,和归一化的暗物质信号。这种简并性可以通过N体模拟或观测对次晕质量函数的约束来打破。

英文摘要:

In the cold dark matter scenario, galactic dark matter halos are populated with a large number of smaller subhalos. Previous work has shown that dark matter annihilations in subhalos can generate a distinctive, non-Poisson signal in the gamma-ray photon counts probability distribution function (PDF). Here we show that the gamma-ray PDF also carries information about the velocity dependence of the dark matter annihilation cross section. After calculating the PDF assuming $s$-wave and Sommerfeld-enhanced annihilation, we perform a mock data analysis to illustrate how current and future observations can constrain the microphysics of the dark matter annihilation. We find that, with current Fermi data, and assuming a dark matter annihilation cross section roughly at the limit of current bounds from annihilation in dwarf spheroidal galaxies, one can potentially distinguish the non-Poissonian fluctuations expected from dark matter annihilation in subhalos from Poisson sources, as well as from dark matter models with an incorrect velocity-dependence. We explore how robust these results are to assumptions about the modeling of astrophysical backgrounds. We also point out a four-parameter degeneracy between the velocity dependence of the dark matter annihilation, the minimum subhalo mass, the power law index of the subhalo mass function, and the normalization of the dark matter signal. This degeneracy can be broken with priors from N-body simulations or from observational constraints on the subhalo mass function.

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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