M87 has been the target of numerous astronomical observations across the electromagnetic spectrum, and very long baseline interferometry has resolved an edge-brightened jet^1,2,3,4. However, the origin and formation of its jets remain unclear. In our current understanding, black holes (BH) are the driving engine of jet formation⁵, and indeed the recent Event Horizon Telescope observations revealed a ring-like structure in agreement with theoretical models of accretion onto a rotating Kerr BH⁶. In addition to the spin of the BH being a potential source of energy for the launching mechanism, magnetic fields are believed to play a key role in the formation of relativistic jets^7,8. A priori, the spin, a_⋆, of the BH in M87^⋆ is unknown; however, when accounting for the estimates of the X-ray luminosity and jet power, values of \(\left|{a}_{\star }\right|\gtrsim 0.5\) appear favoured⁶. Besides the properties of the accretion flow and the BH spin, the radiation microphysics including the particle distribution (thermal⁶ and non-thermal^9,10) as well as the particle acceleration mechanism¹¹ play a crucial role. We show that general relativistic magnetohydrodynamic simulations and general relativistic radiative transfer calculations can reproduce the broadband spectrum from the radio to the near-infrared regime and simultaneously match the observed collimation profile of M87, thus allowing us to set rough constraints on the dimensionless spin of M87* to be 0.5 ≲ a_⋆ ≲ 1.0, with higher spins being possibly favoured.

M87 一直是整个电磁光谱中众多天文观测的目标，并且非常长的基线干涉测量已经解决了边缘增亮的射流^1,2,3,4。然而，其喷流的起源和形成仍不清楚。在我们目前的理解中，黑洞 (BH) 是喷流形成的驱动引擎⁵，事实上，最近的事件视界望远镜观测揭示了一个环状结构，这与吸积到旋转的 Kerr BH ⁶上的理论模型一致。除了 BH 的自旋是发射机制的潜在能量来源之外，磁场被认为在相对论射流的形成中起关键作用^7,8。先验，自旋，a _⋆，在 M87 中的 BH ^⋆未知；然而，当考虑到 X 射线光度和射流功率的估计值时，\(\left|{a}_{\star }\right|\gtrsim 0.5\) 的值似乎更受欢迎⁶。除了吸积流和 BH 自旋的性质外，辐射微物理学包括粒子分布（热⁶和非热^9,10）以及粒子加速机制¹¹起到至关重要的作用。我们表明，广义相对论磁流体动力学模拟和广义相对论辐射传输计算可以再现从无线电到近红外区域的宽带光谱，同时与观测到的 M87 的准直剖面相匹配，从而使我们能够对 M87 的无量纲自旋设置粗略的约束* 为 0.5  ≲  a _⋆  ≲  1.0，可能倾向于更高的旋转。