Reviewed by Louis CastelJan 20 2025
Researchers from the University of Arizona and Max Planck Institute for Astronomy, Germany have now created the sharpest direct infrared images of active galactic nuclei using the Large Binocular Telescope Interferometer. The journal Nature Astronomy published the results.
An image of the spiral galaxy NGC 1086 obtained by the European Southern Observatory’s Very Large Telescope (VLT). The galaxy has a distance of 47 million light-years and is one of the nearest galaxies with an active galactic nucleus. Image Credit: European Southern Observatory
Supermassive black holes at the core of some galaxies are known as active galactic nuclei (AGN). AGN are among the most energetic objects that can be seen in space because of the massive amounts of energy released when matter falls into these black holes.
The Large Binocular Telescope Interferometer can be considered the first extremely large telescope, so it is very exciting to prove this is possible.
Jacob Isbell, Postdoctoral Research Associate and Study Lead Author, Steward Observatory, The University of Arizona
At the core of some galaxies is a supermassive black hole. Depending on how fast material falls into them, some are regarded as active and others as inactive, according to Isbell. The more material falls into the black hole, the brighter the disk surrounding it glows.
This accretion disk is referred to as an active supermassive black hole if it glows sufficiently brightly. The AGN located in the galaxy NGC 1068, a neighbor of the Milky Way, is one of the closest known active galactic nuclei.
The Large Binocular Telescope is situated on Mount Graham, northeast of Tucson. It functions as two independent telescopes mounted side by side, controlling its two 8.4 m mirrors independently.
By combining the light from both mirrors, the Large Binocular Telescope Interferometer makes observations with significantly higher resolution than would be achievable with just one mirror. High-quality images are produced by the interferometer, which turns the two mirrors into a single telescope.
Previous studies of volcanoes on the surface of Jupiter's moon Io have been accomplished with success using this imaging technique. The researchers were inspired by the Io results to examine an AGN with the interferometer.
The AGN within the galaxy NGC 1068 is especially bright, so it was the perfect opportunity to test this method. These are the highest resolution direct images of an AGN taken so far.
Jacob Isbell, Postdoctoral Research Associate and Study Lead Author, Steward Observatory, The University of Arizona
Steve Ertel, an Associate Astronomer at Steward Observatory, is the team leader for the Large Binocular Telescope Interferometer. The team was able to witness multiple simultaneous cosmic phenomena occurring in the AGN, thanks to the interferometer.
The bright disk surrounding the supermassive black hole emits intense light, which exerts radiation pressure, pushing dust away like countless tiny sails. The pictures showed an outflowing, dusty wind brought on by radiation pressure.
At the same time, much of the material farther out was much brighter than it should have been if it had only been lit by the bright accretion disk. By comparing the new images to earlier observations, researchers were able to link this discovery to a radio jet that is blazing through the galaxy, striking and heating clouds of dust and molecular gas.
The interaction between strong radiation and particle jets released by supermassive black holes and their surroundings is known as radio jet feedback.
Direct imaging with exceptionally large telescopes, such as the Large Binocular Telescope Interferometer and the upcoming 83.5-foot Giant Magellan Telescope in Chile, allows for the simultaneous distinction of feedback from the radio jet and dusty wind. Previously, these processes were indistinguishable due to low resolution, but now, thanks to enhanced capabilities, their individual impacts can be observed, according to Isbell.
The study demonstrates that AGN environments can be complicated, and the discoveries will help in understanding how AGNs interact with their host galaxies.
Isbell noted, “This type of imaging can be used on any astronomical object. We have already started looking at disks around stars or very large, evolved stars, which have dusty envelopes around them.”
The study was funded by the National Aeronautics and Space Administration through the Exoplanet Research Program and the French Agence Nationale de la Recherche.
Journal Reference:
Isbell, J. W., et al. (2025) Direct imaging of active galactic nucleus outflows and their origin with the 23 m Large Binocular Telescope. Nature Astronomy. doi.org/10.1038/s41550-024-02461-y.