The James-Webb space telescope has observed gas filaments feeding the supermassive black hole at the center of galaxy NGC 4696. These images show, with an unprecedented level of detail, how matter could be heated, cooled, and then brought back toward the galaxy's core.
NGC 4696 is located about 145 million light-years away. Its core hosts an active black hole, surrounded by a rotating disk of gas. As matter approaches, it releases considerable energy before crossing the boundary beyond which nothing can escape.
Image of the elliptical galaxy NGC 4696, located at the center of the Centaurus cluster, taken by the Hubble Space Telescope. This image reveals dust filaments surrounding the galaxy's center.
Photo credit: NASA, ESA/Hubble, A. Fabian
The black hole's activity also produces jets and winds that expel energy into the galaxy. This mechanism should normally limit the amount of available matter. Yet some black holes continue to grow despite this reaction...
James-Webb's observations provide an answer. They reveal a vast swirl of gas about 800 light-years in diameter, connected to a filamentary structure that leads matter toward the central disk.
The gas expelled by the core's activity can gradually cool down. As it condenses, it then forms long, narrow filaments. These can fall back toward the galactic center under gravity and provide a new supply of matter to the black hole.
The process resembles a feeding loop. The black hole injects energy into its environment, this energy modifies the gas, then part of the cooled gas returns to it. This mechanism could prevent both completely uncontrolled growth and a definitive halt of accretion.
The observed gas velocity reaches up to about 600 kilometers per second. These movements give researchers information about the black hole's mass, the disk's structure, and the interactions between the active nucleus and the surrounding galaxy.
The results, published in the Astrophysical Journal Letters, concern a relatively nearby galaxy. Similar observations of other active nuclei will be necessary to determine whether this loop constitutes a general mechanism or a particular behavior of NGC 4696.