标题： Bondi-Hoyle-Lyttleton 吸积到具有超轻标量毛发的旋转黑洞 显示英文标题

标题： Bondi-Hoyle-Lyttleton accretion onto a rotating black hole with ultralight scalar hair

摘要： 我们对相对论Bondi-Hoyle-Lyttleton（BHL）吸积过程进行了数值研究，该过程发生在具有同步毛发的渐近平坦黑洞上。 毛发由一个超轻的复标量场产生，并与爱因斯坦引力最小耦合。 我们的模拟考虑了由流体量的渐近值参数化的超音速流，以及不同质量、角动量和标量毛发量的毛发黑洞样本。 对于所有模型，都获得了稳态BHL吸积解，这些解的特点是存在一个激波锥和下游的停滞点。 对于样本中具有最大标量场分量的模型，激波锥完全包围黑洞，转变为弓形激波，停滞点向下游移动更远。 在拟合数值结果后得到了质量吸积率的解析表达式，可用于分析存在超轻标量场时黑洞形成场景。 激波锥的形成导致声波可以被俘获并激发共振振荡的区域。 我们测量了这种准周期振荡的频率，并指出可能与Sgr A*和微类星体的X射线光变曲线中的准周期振荡有关。 显示英文摘要

摘要： We present a numerical study of relativistic Bondi-Hoyle-Lyttleton (BHL) accretion onto an asymptotically flat black hole with synchronized hair. The hair is sourced by an ultralight, complex scalar field, minimally coupled to Einstein's gravity. Our simulations consider a supersonic flow parametrized by the asymptotic values of the fluid quantities and a sample of hairy black holes with different masses, angular momenta, and amount of scalar hair. For all models, steady-state BHL accretion solutions are attained that are characterized by the presence of a shock-cone and a stagnation point downstream. For the models of the sample with the largest component of scalar field, the shock-cone envelops fully the black hole, transitioning into a bow-shock, and the stagnation points move further away downstream. Analytical expressions for the mass accretion rates are obtained after fitting the numerical results, which can be used to analyze black-hole formation scenarios in the presence of ultralight scalar fields. The formation of a shock-cone leads to regions where sound waves can be trapped and resonant oscillations excited. We measure the frequencies of such quasi-periodic oscillations and point out a possible association with quasi-periodic oscillations in the X-ray light curve of Sgr~A* and microquasars.