The Dark Matter Annihilation Signal from Galactic Substructure: Predictions for GLAST
The Dark Matter Annihilation Signal from Galactic Substructure: Predictions for GLAST
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DOI：
10.1086/590337
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发表时间：
2008-05
期刊：
影响因子：
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通讯作者：
M. Kuhlen;J. Diemand;P. Madau
中科院分区：
文献类型：
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作者：
M. Kuhlen;J. Diemand;P. Madau
我们提出了定量预测的可探测性的个别银河系暗物质subhalos在伽马射线暗物质对湮灭在其中心。我们的方法基于混合方法，采用最高分辨率的数值模拟（包括最近完成的10亿粒子Via Lactea II模拟）以及分析模型，用于外推超出模拟的分辨率限制。我们包括一个自洽的治疗subhalo的助推因子，我们的数值结果的动机，和一个现实的治疗预期的背景，个人subhalos必须脱颖而出。我们证明，对于暗物质粒子物理参数的合理值（Mχ = 50-500 GeV和<$σ v = 10−26-10−25 cm 3 s−1），GLAST很可能发现几个，甚至几十个这样的5 σ显著性的次晕，有些超过20 σ。我们预测，大多数光源将与GLAST的预期角分辨率解决。对于大多数观测者的位置，可探测到的暗晕的角分布与整个天空的均匀分布是一致的。最明亮的暗晕往往质量很大（中值Vmax为24 km s−1），因此可能是矮星系的宿主，但也可以看到许多Vmax低至5 km s−1的暗晕。通常可探测到的次晕距离观测者20-40千秒差距，只有一小部分比10千秒差距更近。在我们的模拟中，可观测到的subhalos的总数尚未收敛，我们估计我们可能会错过所有可探测到的subhalos的3/4。
We present quantitative predictions for the detectability of individual Galactic dark matter subhalos in gamma rays from dark matter pair annihilations in their centers. Our method is based on a hybrid approach, employing the highest resolution numerical simulations available (including the recently completed 1 billion particle Via Lactea II simulation), as well as analytical models, for extrapolating beyond the simulations’ resolution limit. We include a self-consistent treatment of subhalo boost factors, motivated by our numerical results, and a realistic treatment of the expected backgrounds that individual subhalos must outshine. We show that for reasonable values of the dark matter particle physics parameters (Mχ ∼ 50-500 GeV and ⟨ σ v⟩ ∼ 10−26-10−25 cm3 s−1) GLAST may very well discover a few, even up to several dozen, such subhalos at 5 σ significance, and some at more than 20 σ. We predict that the majority of luminous sources would be resolved with GLAST’s expected angular resolution. For most observer locations, the angular distribution of detectable subhalos is consistent with a uniform distribution across the sky. The brightest subhalos tend to be massive (median Vmax of 24 km s−1) and therefore likely hosts of dwarf galaxies, but many subhalos with Vmax as low as 5 km s−1 are also visible. Typically detectable subhalos are 20-40 kpc from the observer, and only a small fraction are closer than 10 kpc. The total number of observable subhalos has not yet converged in our simulations, and we estimate that we may be missing up to 3/4 of all detectable subhalos.