Our knowledge of black holes is incomplete. We know there are stellar mass black holes that are created when massive stars collapse on themselves at the end of their lives of fusion. We know that supermassive black holes reside in the hearts of galaxies and sometimes merge with each other. The fact that there are two other hypothetical types of black holes that may or may not exist—primordial black holes and intermediate mass black holes—illustrates how our understanding is lacking.
The main reason for our incomplete knowledge is the difficulties in observing them. Most galaxies seem to host black holes in their centers, but they’re only directly observable when they’re accreting material and emitting light. These are active galactic nuclei (AGN).
A team of astronomers have detected an AGN in a distant dwarf galaxy about 230 million light years away. In a twist, this black hole doesn’t reside in its galactic center. Instead, its off-center by about 3,200 light years. It’s not the only one.
The discovery is in new research in the journal Science Bulletin. It’s titled “A jetted wandering massive black hole candidate in a dwarf galaxy,” and the lead author is Yuanqi Liu from the Shanghai Astronomical Observatory.
The new discovery is an offset massive black hole that’s actively accreting material like an AGN and is also producing the signature jets of an AGN. It shows that black holes can actively accrete material and grow even when not situated in the galactic center. This is surprising, since galactic centers are known to host large reservoirs of gas that black holes feed on.
“Off-nuclear(or offset) active galactic nucleus (AGN) are increasingly recognized as important laboratories for understanding galactic dynamics and black-hole evolution, with recent studies indicating that they are quite common in various galaxy populations,” the authors of the new research write.
This artist’s illustration shows an AGN emitting jets and radiation as it accretes gas. While typically found in galactic centers, the researchers found a black hole/AGN over 3200 light years from the center of its dwarf galaxy. Image Credit: NASA, ESA, CSA, Joseph Olmsted (STScI)
Astronomers are interested in studying black holes in dwarf galaxies. Dwarf galaxies have simpler evolutionary histories and lower masses than large galaxies like the Milky Way. That means that evidence of the processes that shaped their black holes’ is better preserved than in more massive galaxies.
Dwarf galaxies also have shallower gravity wells simply because they’re less massive. Research shows that events like galaxy mergers or interactions involving multiple other bodies are enough to kick black holes out of the centers of dwarf galaxies. This is likely what happened in this case.
This new discovery comes from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. MaNGA is mapping about 10,000 galaxies, and investigating their internal kinematic structures and the composition of gas and stars. It has identified 628 dwarf galaxies with candidate AGN. Of those 628 AGN, about 390 of them, or 62%, may be offset from their galactic centers.
In this research, the team used the Very Long Baseline Array to study a dwarf galaxy named MaNGA 12772-12704. Since the host galaxy shows no signs of merger activity, like tidal tails or double nuclei, they concluded that what they found is an offset black hole. The researchers calculated that the black hole has about 300,000 solar masses, meaning it could be in the range of the elusive intermediate black holes, depending on the definition.
This study shows that off-center black holes can grow even though they’re not firmly in the galactic center, where gas is readily available for them to accrete. The discovery is direct evidence that supports an alternate method of black hole growth. Astrophysicists know that black holes can grow through accretion and through mergers as their host galaxies merge. Gravitational wave observations confirm this. But this study shows that black holes can become more massive without mergers and without needing to be near the galactic center and its gas reservoir.
An artist’s illustration of two black holes merging. Image Credit: LIGO/T Pyle
“This discovery prompts us to rethink black hole–galaxy co-evolution,” said co-author Tao An in a press release. “Black holes are not only central ‘engines’ but may also quietly reshape their host galaxies from the outskirts.”
“The implications are profound especially for the SMBH formation in the early Universe, where traditional models struggle to explain the rapid growth of SMBHs” to one billion masses the authors explain in their research. The general model of black hole growth in galaxies supposes efficient, steady, and sustained growth through gas that’s funneled into the galactic center.
The left panel shows the spatial distribution of ionization across the galaxy, with the black star showing the position of the black hole. The right panel shows SDSS observations in its g-band, used to identify AGN. It also shows radio contours from the FIRST survey, showing that the AGN is offset. Image Credit: Liu et al. 2025. Science Bulletin.
“MaNGA 12772-12704 suggests an alternative pathway: black holes may grow through accretion events distributed throughout their host galaxy,” the researchers write. Since the early Universe featured chaotic, gas-rich galaxies, this alternative pathway may be even more relevant.
The discovery also forces scientists to reconsider how AGN feedback, an important process in galaxies, works in low-mass dwarf galaxies. “These observations suggest that even displaced MBHs can drive mechanical feedback, impacting star formation and gas dynamics within their host galaxies,” the authors explain in their research. “The well-defined jet in this off-nuclear AGN shows that accretion disk-jet systems, commonly seen in powerful AGN within massive galaxies, can form and sustain beyond galactic centre, broadening our insights into AGN physics.”
This discovery is helping shift wandering black holes from the hypothetical to the observationally confirmed. As more powerful telescopes come online, astronomers may find and confirm more of them, including the hundreds that are in limbo as candidates. Once astronomers can observe galaxy centers and structures with greater accuracy, they may find that offset AGN are not rare, at least in dwarf galaxies.
As a result, our understanding of black holes, the Universe’s most beguiling objects, will take a huge step forward.