A supermassive black hole from the early universe is challenging existing theories about black hole growth. This object, designated ID830, isn’t just growing rapidly – it’s doing so at a rate that appears to defy established physical limits, and simultaneously emitting both intense X-rays and radio waves, a combination previously considered unlikely.
ID830 is an exceptionally bright and active quasar, characterized by powerful bursts of radiation emanating from its poles. Simultaneously, material spiraling into the black hole generates strong X-ray emissions as it rapidly orbits. Astronomers estimate that approximately 12 billion years ago, when the universe was only about 15 percent of its current age, ID830 already possessed a mass roughly 440 million times that of our Sun. This represents more than 100 times the mass of Sagittarius A*, the black hole at the center of the Milky Way galaxy.
Researchers from Waseda University and Tohoku University, utilizing the Subaru Telescope, detailed their findings in a study published on , in The Astrophysical Journal. The team observed ID830 across a wide spectrum of wavelengths to understand the mechanisms driving its unusual behavior.
The growth of black holes is generally believed to be constrained by a process known as the Eddington limit. This limit arises because the radiation pressure from material falling into the black hole counteracts the inward pull of gravity, effectively slowing down the accretion rate. However, black holes can temporarily exceed this limit during phases of “super-Eddington” accretion. As Anthony Taylor, an astronomer at the University of Texas at Austin who was not involved in the study, explained, “It should be perfectly possible for a black hole to consume material faster than the Eddington limit for a short period before the radiation pressure builds up and limits the accretion rate.”
The research team calculated ID830’s growth rate by measuring its ultraviolet and X-ray brightness. Their analysis indicates that this quasar is accreting matter approximately 13 times faster than the Eddington limit would allow. One potential explanation for this rapid growth is a sudden influx of gas, perhaps triggered by ID830 disrupting and consuming a passing celestial object.
Sakiko Obuchi, an observational astronomer at Waseda University in Tokyo and a co-author of the study, noted that fueling such rapid growth requires substantial material. “For an SMBH the size of ID830, this would require not normal stars, but more massive giant stars or a very large gas cloud.” She added that these super-Eddington phases are expected to be relatively short-lived, lasting only around 300 years.
Adding to the intrigue is the simultaneous presence of both radio and X-ray emissions. This combination is considered unusual because super-Eddington accretion is often thought to suppress the emergence of these emissions. Researchers believe this suggests the presence of physical mechanisms within the quasar that are not yet fully understood in current models of jet formation and extreme accretion.
The behavior of ID830 provides a glimpse into a rare transitional phase where a black hole is experiencing an exceptionally intense “feeding frenzy.” The immense energy released not only accelerates its growth but also has the potential to influence the surrounding galactic environment by heating and dispersing interstellar gas, potentially inhibiting the formation of new stars.
This discovery offers crucial insights into how supermassive black holes could have grown so rapidly in the early universe, and how they, in turn, shaped the evolution of the galaxies they inhabit. The findings highlight the complexity of black hole physics and the need for continued research to refine our understanding of these cosmic giants.