2MASX J23453268-0449256 (J2345-0449 for short), an extremely massive, rapidly rotating, jet-launching spiral galaxy approximately 947 million light-years in the constellation of Aquarius, harbors a supermassive black hole billions of times the Sun’s mass which is powering colossal radio jets stretching 6 million light-years across. That is one of the largest known for any spiral galaxy and upends conventional wisdom of galaxy evolution, because such powerful jets are almost exclusively found in elliptical galaxies, not spirals. It also means the Milky Way could potentially create similar energetic jets in the future.
This image shows the spiral galaxy 2MASX J23453268-0449256 and its giant radio jets. Image credit: Bagchi et al. / Giant Metrewave Radio Telescope.
“This discovery is more than just an oddity — it forces us to rethink how galaxies evolve, and how supermassive black holes grow in them and shape their environments,” said CHRIST University’s Professor Joydeep Bagchi.
“If a spiral galaxy can not only survive but thrive under such extreme conditions, what does this mean for the future of galaxies like our own Milky Way?”
“Could our Galaxy one day experience similar high-energy phenomena that will have serious consequences for the survival of precious life in it?”
In the new study, the astronomers unravelled the structure and evolution of the spiral galaxy J2345-0449, which is three times the size of the Milky Way.
Using observations from the NASA/ESA Hubble Space Telescope, the Giant Metrewave Radio Telescope, the Atacama Large Millimeter/submillimeter Array (ALMA) and multi-wavelength analyses, they detected an enormous supermassive black hole at its heart and radio jets that are among the largest known for any spiral galaxy, making it a rare phenomenon.
Traditionally, scientists believed that the violent activity of such colossal jets of supermassive black holes would disrupt the delicate structure of a spiral galaxy.
Yet, against all odds, J2345-0449 has retained its tranquil nature with well-defined spiral arms, a luminous nuclear bar, and an undisturbed stellar ring — all while hosting one of the most extreme black holes ever observed in such a setting.
Adding to the enigma, the galaxy is surrounded by a vast halo of hot, X-ray-emitting gas, providing key insights into its history.
While this halo slowly cools over time, the black hole’s jets act like a cosmic furnace, preventing new star formation despite the presence of abundant star-making material.
The authors also discovered that J2345-0449 contains 10 times more dark matter than the Milky Way, which is crucial for stability of its fast spinning disk.
“Understanding these rare galaxies could provide vital clues about the unseen forces governing the Universe — including the nature of dark matter, the long-term fate of galaxies, and the origin of life,” said Shankar Ray, a Ph.D. student at CHRIST University.
“Ultimately, this study brings us one step closer to unravelling the mysteries of the cosmos, reminding us that the Universe still holds surprises beyond our imagination.”
The findings were published in the Monthly Notices of the Royal Astronomical Society.
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Joydeep Bagchi et al. 2025. Unveiling the bulge-disc structure, AGN feedback, and baryon landscape in a massive spiral galaxy with Mpc-scale radio jets. MNRAS 538 (3): 1628-1652; doi: 10.1093/mnras/staf229
