Evaporating the Milky Way halo and its satellites with inelastic self-interacting dark matter
Evaporating the Milky Way halo and its satellites with inelastic self-interacting dark matter
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DOI：
10.1093/mnras/stz340
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发表时间：
2018-05
影响因子：
4.8
通讯作者：
M. Vogelsberger;J. Zavala;K. Schutz;T. Slatyer
中科院分区：
文献类型：
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作者：
M. Vogelsberger;J. Zavala;K. Schutz;T. Slatyer
自相互作用暗物质为冷暗物质范式解决潜在的小尺度星系形成问题提供了一个有希望的替代方案。到目前为止，几乎所有的自相互作用暗物质模拟都只考虑了弹性碰撞。本文利用Arepo代码中的一种新颖的数值实现，在一般非弹性模型中模拟了星系晕，以研究任意多态非弹性暗物质场景。对于该模型，我们发现非弹性自相互作用可以：(i)与相同截面归一化的弹性模型相比，产生更大的亚晕密度核；（ii）降低卫星数量，而无需功率谱截断；（iii）使总光晕质量降低约10%；（iv）通过能级去激发向星系晕注入相当于0(1)亿个II型超新星的能量；(v)避免因粒子从光晕中心移出而引起的重热突变。我们得出的结论是，要达到与非弹性模型相同的中心密度降低，需要大5倍的弹性截面。这意味着，如果非弹性碰撞是主要模式，则必须修改对自相互作用截面的既定约束。在这种情况下，更小的横截面可以实现相同的核心密度降低，从而大大增加了允许模型的参数空间。
Self-interacting dark matter provides a promising alternative for the cold dark matter paradigm to solve potential small-scale galaxy formation problems. Nearly all self-interacting dark matter simulations so far have considered only elastic collisions. Here we present simulations of a galactic halo within a generic inelastic model using a novel numerical implementation in the Arepo code to study arbitrary multi-state inelastic dark matter scenarios. For this model we find that inelastic self-interactions can: (i) create larger subhalo density cores compared to elastic models for the same cross section normalisation; (ii) lower the abundance of satellites without the need for a power spectrum cutoff; (iii) reduce the total halo mass by about 10%; (iv) inject the energy equivalent of O(100) million Type II supernovae in galactic haloes through level de-excitation; (v) avoid the gravothermal catastrophe due to removal of particles from halo centers. We conclude that a ~5 times larger elastic cross section is required to achieve the same central density reduction as the inelastic model. This implies that well-established constraints on self-interacting cross sections have to be revised if inelastic collisions are the dominant mode. In this case significantly smaller cross sections can achieve the same core density reduction thereby increasing the parameter space of allowed models considerably.