The galactic 511 keV gamma-ray line has been observed since 1970's, and was identified as the result of electron-positron annihilation, but the origin of such positrons is still not clear. Apart from the astrophysical explanations, the possibilities that such positrons come from dark matter (DM) annihilation are also widely studied. Primordial black hole (PBH) is also an extensively studied candidate of DM. If PBHs exist, the DM particles may be gravitationally bound to the PBHs and form halo around PBHs with density spikes. DM annihilation in these density spikes can enhance the production rate of positrons from DM particles, but the signal morphology is similar to the decaying DM. We consider such a mixed model consisting of DM particles and PBHs and obtain the upper limit from the data of 511 keV gamma-ray line from INTEGRAL/SPI on the decaying component of DM particles and the constraint on the PBH abundance. These constraints are general and independent of particle DM models. For the mixed model consisting of excited DM and PBHs, the constraints on the PBH abundance can be down to O(10^-17) for DM particle with mass around 1, which is more stringent than that obtained from the extragalactic gamma-ray background.

银河系 511 keV 伽马射线线自 1970 年代以来一直被观测到，并被确定为正电子湮灭的结果，但这种正电子的起源仍不清楚。除了天体物理学的解释，这些正电子来自暗物质（DM）湮灭的可能性也被广泛研究。原始黑洞 (PBH) 也是 DM 的一个广泛研究的候选者。如果存在 PBH，DM 粒子可能会在重力作用下与 PBH 结合并在 PBH 周围形成具有密度尖峰的光晕。这些密度尖峰中的 DM 湮灭可以提高 DM 粒子产生正电子的速率，但信号形态类似于衰减的 DM。我们考虑这样一个由DM粒子和PBHs组成的混合模型，并从INTEGRAL/SPI的511 keV伽马射线线数据中获得了DM粒子衰变分量和PBH丰度约束的上限。这些约束是通用的，独立于粒子 DM 模型。对于由激发态 DM 和 PBH 组成的混合模型，对 PBH 丰度的约束可以降至 O(10^-17 ) 对于质量约为 1 的 DM 粒子，这比从河外伽马射线背景获得的更严格。