THE Filaments in the Milky Way. Credit: Farhad Yusef-Zadeh/Northwestern University

Scientists find that hundreds of horizontal filaments point towards the Milky Way’s supermassive black hole

An international team of astrophysicists has discovered something completely new, hidden in the center of our galaxy, the Milky Way. In the early 1980s, Farhad Yusef-Zadeh of Northwestern University discovered giant one-dimensional filaments hanging vertically near Sagittarius A*, the supermassive black hole at the center of our galaxy. Now, Yusef-Zadeh and his collaborators have discovered a new population of filaments, but these threads are much shorter and lie horizontally or radially, extending like the spokes of a wheel from a black hole. Although the two filament populations share several similarities, scientists assume they have different origins. As the vertical filaments traverse the galaxy, reaching up to 150 light-years high, the horizontal strands look more like the dots and dashes of Morse code, dotting just one side of Sagittarius A*. The study builds on four decades of revealing research. almost 1,000 vertical filaments, appearing in pairs and groups, often stacked at the same distance or next to each other like the strings of a harp. While both populations include one-dimensional filaments that can be traced with radio waves and appear to be related to activities in the galactic center, the similarities end there.

Differences between filaments The vertical filaments are perpendicular to the galactic plane; the horizontal filaments are parallel to the plane but point radially towards the center of the galaxy where the black hole is located. The vertical filaments are magnetic and relativistic; the horizontal filaments appear to emit thermal radiation. The vertical filaments enclose particles that move at speeds close to the speed of light; the horizontal filaments appear to accelerate the thermal material into a molecular cloud. There are several hundred vertical filaments and only a few hundred horizontal filaments. And the vertical filaments, which are up to 150 light-years tall, outnumber the horizontal filaments, which are 5 to 10 light-years long. Vertical filaments also outlined the space around the galaxy’s nucleus. The new discovery is full of unknowns and the work of scientists to unravel its mysteries has only just begun.