The Milky Way's Dark Halo is Flattened and Twisted ⚡ экспресс
A dynamical model with minimal assumptions was created, using 6D phase-space data of K-giants (LAMOST+Gaia) to map the 3D distribution of dark matter within ~50 kpc. A triaxial, nearly oblate halo was found, with axes q = Z/X = 0.92±0.08, p = Y/X = 0.8±0.2 (Z axis perpendicular to the disk). With q > p, the plane of the long and middle axes of the halo is oriented vertically to the galactic disk but coincides with the plane of satellites. This points to a flip of the disk (and inner halo) relative to its original orientation, caused by tidal effects of minor mergers, supported by analogs in Auriga and TNG50 simulations. When accounting for the radial dependence of axes, a twisting of the halo is seen: in inner regions it is aligned with the disk, while at r ≳ 20 kpc it transitions to a vertical orientation. Such a reorientation naturally produces the vertical plane of satellites and fits into the ΛCDM model, offering a unified picture of the evolution of the halo, disk, and satellite system.
The Milky Way's stellar disk is like a glowing pinwheel, and тёмное вещество is an invisible cloud around it. For the first time, its shape has been precisely measured. Astronomers tracked the motions of millions of stars and built a 3D map of the тёмное гало out to 160,000 light-years. Back in the day, Фриц Цвикки and Вера Рубин proved the existence of hidden mass, but its distribution remained a mystery.
The picture was stunning. The гало is not spherical, but elongated and flattened, like a deflated rugby ball. And its long axis sticks out almost perpendicular to the stellar disk — as if an invisible frame had been tilted by 90 degrees. This orientation matches the plane in which the dwarf satellite galaxies orbit.
Such a tilt is simply explained: billions of years ago, the Milky Way's disk flipped under the gravitational pressure of small galaxies. Computer simulations confirm this. The discovery ties the стандартная космологическая модель to the actual behavior of galaxies and finally explains the enigmatic plane of satellites.
🎯 There is five times more dark matter than ordinary matter. Without its invisible gravity, galaxies would fly apart from centrifugal force.