The Galactic magnetic field plays an important role in the evolution of the Galaxy, but its small-scale behaviour is still poorly known. It is not known whether the Galactic field permeates the halo of the Galaxy. By observing pulsars in the halo globular cluster 47 Tucanae, we have probed the Galactic magnetic field at arcsecond scales, discovering an unexpected large gradient in the component of the magnetic field parallel to the line of sight. This gradient is aligned with a direction perpendicular to the Galactic disk and could be explained by magnetic fields amplified to some 60 μG within the globular cluster. Such a scenario supports the existence of a magnetized outflow that extends from the Galactic disk to the halo and interacts with 47 Tucanae.

银河磁场在银河系的演化中发挥着重要作用，但它的小尺度行为仍然鲜为人知。目前尚不清楚银河场是否渗透到银河系的光晕中。通过观察晕球状星团 47 Tucanae 中的脉冲星，我们在角秒尺度上探测了银河磁场，发现平行于视线的磁场分量中存在意想不到的大梯度。该梯度与垂直于银盘的方向对齐，可以通过在球状星团内放大到约 60 μG 的磁场来解释。这种情况支持从银盘延伸到光晕并与 47 Tucanae 相互作用的磁化流出的存在。