Self-interacting dark matter (SIDM) naturally gives rise to a cored isothermal density profile, which is favored in observations of many dwarf galaxies. The dark matter distribution in the presence of a central black hole in an isothermal halo develops a density spike with a power law of r ? 7 / 4 , which is shallower than r ? 7 / 3 as expected for collisionless dark matter (CDM). Thus, indirect detection constraints on dark matter annihilations from the density spike could be relaxed in SIDM. Taking the most dense satellite galaxy of the Milky?Way Draco as an example, we derive upper limits on the annihilation cross section and the black hole mass for both SIDM and CDM halos. For the former case, Draco could host an intermediate mass black hole even if dark matter is composed of thermal relics. We further explore the constraints from the Milky?Way and M87, which host supermassive black holes, and show the upper limits on the annihilation cross section are significantly weakened in SIDM. Our results also indicate that the Event Horizon Telescope could provide a unique test of SIDM spikes.
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机译：自相互作用的暗物质（SIDM）自然地产生芯片等温密度曲线，这在许多矮星的观察中受到青睐。在等温光环中的中央黑洞存在下的暗物质分布在r的电力法发育密度尖峰？ 7/4，比慢于r？ 7/3预期的碰撞暗物质（CDM）。因此，在SIDM中可以放松来自密度尖峰的暗质量湮灭的间接检测约束。以乳白色的最密集的卫星银河系是Draco作为一个例子，我们可以为SIDM和CDM Halos的湮灭横截面和黑洞质量产生上限。对于前案例，即使暗物质由热遗物组成，Draco也可能举办中间质量黑洞。我们进一步探索了乳白色的约束，宿主黑洞的方式和M87，并显示湮灭横截面上的上限在SIDM中显着削弱。我们的结果还表明，事件Horizo n Telescope可以提供SIDM Spikes的独特测试。
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