The quasar in galaxy J0218-0036 ran out of gas on a 20-year human timescale. Standard models say this should take millennia. Dust does not explain it. The host galaxy now outshines what was once its luminous core.
image from Gemini Imagen 4
A quasar in galaxy J0218-0036 located ~14-15 billion light-years away faded to 1/20th of its original brightness over roughly 20 years of observation, with its mass accretion rate plummeting 50-fold in just 7 years. The Eddington ratio dropped from ~0.4 to ~0.008 over this period—20 times the typical AGN variability range—in what appears to be a fuel-exhaustion event. This challenges the prevailing assumption that supermassive black hole accretion rates vary over tens of thousands of years or longer, suggesting such transitions can occur on human timescales.
A black hole roughly 14 to 15 billion light-years away has gone quiet. Not over millions of years — over the span of a human career.
The quasar in galaxy J0218-0036, formally cataloged as SDSS J021801.90-003657.7, faded to roughly one-twentieth of its previous brightness over approximately twenty years of observation, according to a 14-author international team published in the Publications of the Astronomical Society of Japan (PASJ) on November 4, 2025. The mass accretion rate — the rate at which gas falls from the accretion disk into the black hole — dropped to about one-fiftieth of its former level in only about seven years, the Subaru Telescope team reported. The active nucleus is now so dim the host galaxy itself outshines it in the optical range.
The numbers are not subtle. The Eddington ratio, a measure of how fast the black hole is feeding relative to its theoretical maximum, fell from approximately 0.4 to roughly 0.008 — a factor of fifty decline, according to the PASJ paper. Typical active galactic nuclei wobble in brightness by around 30 percent over cosmic timescales. This is twenty times that range in a human lifetime.
Supermassive black holes sit at the center of most large galaxies. When gas flows inward through the accretion disk, it heats up and radiates light across the spectrum — the quasar is that light. The standard picture of how these systems evolve says the feeding process is slow. Mass accretion onto supermassive black holes was generally thought to vary over tens of thousands of years or longer. The new result, if it holds, says that timescale can be orders of magnitude shorter.
The team, led by Tomoki Morokuma, Principal Staff Scientist at the Astronomy Research Center at Chiba Institute of Technology in Japan, identified the quasar by cross-matching historical photographic plates from the 1950s through the 1990s with modern survey data from the Subaru Hyper Suprime-Cam (HSC) and the Sloan Digital Sky Survey (SDSS). They then ran follow-up spectroscopy and near-infrared imaging on the Gran Telescopio Canarias (GTC) in the Canary Islands, the Keck Observatory in Hawaii, and the SOAR Telescope in Chile.
What they found is consistent across seven decades of imaging data: the quasar was bright in archival plates from the 1980s and 1990s. By the time HSC observed it in the 2010s, it had dimmed substantially. The feeding event that powered the quasar ran out of fuel.
"It is fascinating that an active galactic nucleus can change its brightness so dramatically over such a short period of time, and that this fading appears to be caused by a large change in the accretion rate onto the supermassive black hole," Morokuma said in a Subaru Telescope press release.
Co-author Toshihiro Kawaguchi at the University of Toyama put it more directly: standard models cannot account for this kind of variability, and the object provides an important test case for new theoretical models. The expected timescales for accretion-driven brightness changes are orders of magnitude longer than what this object is showing.
The researchers ruled out a simpler explanation: a cloud of dust passing between us and the quasar would also dim the light, but dust affects different wavelengths differently. The dimming observed in J0218-0036 is consistent across optical and near-infrared bands — a signature of genuine loss in the central engine rather than a line-of-sight screen, the paper states. This is a real change in how much matter the black hole is swallowing.
The finding has consequences for how astronomers think about galaxy evolution. The growth of a supermassive black hole and the evolution of its host galaxy are linked — the energy released by accretion regulates star formation in the surrounding galaxy, a feedback mechanism that shapes both objects over cosmic time. If black holes can exhaust their fuel supply in decades rather than millennia, the timing and intensity of that feedback changes. Quasar lifetimes, the conditions that trigger active and dormant phases, the relationship between black hole mass and galaxy properties — all of it may need recalibration.
The quasar in J0218-0036 is now essentially quiet. Its host galaxy, previously overwhelmed by the active nucleus's light, is visible in the data as the dominant source of optical emission. The black hole is still there. It is just no longer feeding.
The dataset covers one object. Whether this is a common phenomenon — a phase that most supermassive black holes pass through, or a rare event — is the next question. Morokuma's team examined approximately 31,500 quasars in the overlap between SDSS and HSC surveys across 421 square degrees of sky and found this one striking case. Larger time-domain surveys coming online, including the Vera C. Rubin Observatory's Legacy Survey of Space and Time, will be able to watch many more active nuclei over longer periods and determine how unusual this dimming event is.
The paper is published in PASJ with a free preprint on arXiv. The Universe Today article on this story is a rehash of the Subaru press release and adds nothing new — the primary sources are the telescope teams and the paper itself.
Story entered the newsroom
Research completed — 0 sources registered. Galaxy J0218-0036 (z=1.767, ~10B ly away) faded by factor of 20-30 in optical brightness over 20 years. AGN accretion rate dropped to 1/50th of previo
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Headline selected: Black Hole Went Quiet in a Human Lifetime
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