Dark matter heating of gas accreting onto Sgr A*
Dark matter heating of gas accreting onto Sgr A*
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DOI：
10.1093/mnras/stz2781
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发表时间：
2019-06
影响因子：
4.8
通讯作者：
Elizabeth R. Bennewitz;Cristian Gaidău;T. Baumgarte;S. Shapiro
中科院分区：
文献类型：
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作者：
Elizabeth R. Bennewitz;Cristian Gaidău;T. Baumgarte;S. Shapiro
研究了暗物质湮灭加热对黑洞气体吸积的影响。我们观察到，对于合理的假设DM密度的尖峰周围的超大质量黑洞，以及DM质量和湮灭截面内的标准WIMP模型，加热DM湮灭可能有一个可观的影响上的吸积到银河系中心的Sgr A*。出于这一观察，我们研究的影响，这种加热的邦迪吸积，即球对称，稳态牛顿吸积的黑洞。我们考虑不同的绝热指数的气体，和不同的幂律指数的DM密度分布。我们发现，典型的跨音速加热的解决方案有一个显着降低吸积率。然而，对于许多合理的参数，跨音速的解决方案并不存在，这表明稳态邦迪吸积的基本假设的故障。我们的研究结果表明，DM湮灭加热可能在星系中心超大质量黑洞的吸积中发挥重要作用，并可能有助于解释Sgr A* 的低吸积率。
We study effects of heating by dark matter (DM) annihilation on black hole gas accretion. We observe that, for reasonable assumptions about DM densities in spikes around supermassive black holes, as well as DM masses and annihilation cross-sections within the standard WIMP model, heating by DM annihilation may have an appreciable effect on the accretion on to Sgr A* in the Galactic Centre. Motivated by this observation we study the effects of such heating on Bondi accretion, i.e. spherically symmetric, steady-state Newtonian accretion on to a black hole. We consider different adiabatic indices for the gas, and different power-law exponents for the DM density profile. We find that typical transonic solutions with heating have a significantly reduced accretion rate. However, for many plausible parameters, transonic solutions do not exist, suggesting a breakdown of the underlying assumptions of steady-state Bondi accretion. Our findings indicate that heating by DM annihilation may play an important role in the accretion onto supermassive black holes at the centre of galaxies, and may help explain the low accretion rate observed for Sgr A*.