An international team has discovered a quasar in the early universe hosting a supermassive black hole that grows at an extraordinary rate. Observations reveal it accreting matter 13 times faster than the theoretical limit while emitting strong X-rays and a radio jet. This unusual behavior challenges existing models of black hole development.
Astronomers from Waseda University and Tohoku University, leading an international collaboration, have identified a rare quasar dating back about 12 billion years. Using the Subaru Telescope's near-infrared spectrograph MOIRCS, they analyzed the Mg II emission line to estimate the black hole's mass and accretion rate. The findings indicate the black hole is devouring matter at roughly 13 times the Eddington limit, a theoretical cap on growth due to outward radiation pressure from infalling material.
This quasar, observed at a redshift of z=3.4, stands out for combining super-Eddington accretion with intense X-ray emissions from its corona and a powerful radio jet. Standard models suggest such rapid growth should suppress these features, yet here they coexist, hinting at a transitional phase possibly triggered by a sudden gas influx. The team proposes this captures a brief, unstable spurt in the black hole's evolution, offering clues to how supermassive black holes reached immense sizes in the universe's infancy.
Supermassive black holes, millions to billions of times the sun's mass, anchor most galaxies and grow by pulling in gas that forms an accretion disk. When active, they shine as quasars. The discovery's radio jet suggests it could influence its host galaxy by heating gas and affecting star formation, linking black hole growth to galactic evolution.
Lead author Sakiko Obuchi remarked: "This discovery may bring us closer to understanding how supermassive black holes formed so quickly in the early Universe. We want to investigate what powers the unusually strong X-ray and radio emissions, and whether similar objects have been hiding in survey data."
The research, published in the Astrophysical Journal on January 21, 2026, was conducted from Maunakea, Hawaii, acknowledging its cultural significance.