Hundreds of horizontal filaments have been discovered in the centre of our galaxy – the Milky Way – and these point toward our central supermassive black hole (Sagittarius A*). The finding is based on new radio telescope that show the mysterious filaments along the galactic plane, each measuring 5 to 10 light-years in length.
These structures are thought to have originated a few million years ago when outflow from our supermassive black hole interacted with surrounding materials.
The discovery has been led by Northwestern University’s Farhad Yusef-Zadeh, who reports on the new population of filaments. These threads are much shorter than any previously seen and similar structures. The filaments lie horizontally or radially, spreading out like spokes on a wheel from the black hole.
The horizontal filaments look like the dots and dashes of Morse code, punctuating one side of Sagittarius A*. The black hole itself is not seen; instead, it is detected only through nearby objects whose behaviour is influenced by the black hole.
Yusef-Zadeh says: “I was actually stunned when I saw these. We had to do a lot of work to establish that we weren’t fooling ourselves. And we found that these filaments are not random but appear to be tied to the outflow of our black hole. By studying them, we could learn more about the black hole’s spin and accretion disk orientation. It is satisfying when one finds order in the middle of a chaotic field of the nucleus of our galaxy.”
Yusef-Zadeh credits the new discovery to enhanced radio astronomy technology, particularly the South African Radio Astronomy Observatory’s (SARAO) MeerKAT telescope.
To pinpoint the filaments, Yusef-Zadeh’s team used a technique to remove the background and smooth the noise from MeerKAT images in order to isolate the filaments from surrounding structures.
Yusef-Zadeh estimates the horizontal filaments are about 6 million years old and they appear to be tied to activities in the galactic centre, pointing radially toward the centre of the galaxy where the supermassive black hole lies. In addition, the horizontal filaments appear to accelerate thermal material in a molecular cloud.
The new discovery remains filled with unknowns although it is possible the filaments originated with some kind of outflow from an activity that happened a few million years ago.
The research appears in the journal The Astrophysical Journal Letters, titled “The population of the galactic center filaments: Position angle distribution reveal a degree-scale collimated outflow from Sgr A* along the galactic plane”.
The research was supported by NASA.
