The first billion years of cosmic history present a challenge: early black holes in galaxies have unexpectedly large masses. The new observations argue against the theory of an ultra-effective feeding mode for these early black holes.
The Limits of Supermassive Black Hole Growth
Over the past 13.8 billion years, stars and galaxies have changed significantly. Galaxies have grown by consuming gas or merging. It was assumed that supermassive black holes grew gradually with their host galaxies. However, black hole growth is limited by the pressure exerted by light from the accretion disk around the black hole.
ow Did Black Holes Get So Massive, So Fast?
Astronomers were surprised by observations of distant quasars showing very young black holes with masses up to 10 billion solar masses. These quasars are observed as they were less than one billion years after the Big Bang. Explaining these massive early black holes challenges current models of galaxy evolution.
A Closer Look at Early Black-Hole Growth
To verify existing theories, a complete picture of quasars is required. The JWST's mid-infrared instrument, MIRI, significantly enhances the ability to study distant quasars. In 2019, the MIRI European Consortium used observation time to study J1120+0641, the most distant known quasar at the time.
Observing One of the Earliest Black Holes
Dr. Sarah Bosman, a post-doctoral researcher at the Max Planck Institute for Astronomy (MPIA), analyzed the observations conducted in January 2023. These observations provide the first mid-infrared study of a quasar from the cosmic dawn period, 770 million years after the Big Bang.
Tracing Dust and Fast-Moving Gas
The mid-infrared spectrum indicates a dust torus surrounding the quasar's accretion disk, similar to more modern quasars. The dust temperature was slightly higher than usual. The spectrum also shows that the quasar's light is not excessively dimmed by dust, indicating no overestimation of early black hole masses due to dust.
Early Quasars "Shockingly Normal"
The quasar's broad-line region shows normal properties, suggesting that early quasars are similar to those observed at later times. "Overall, the new observations only add to the mystery: Early quasars were shockingly normal," says Bosman. The results support the idea that supermassive black holes started with considerable masses, forming early with initial masses of at least 100,000 solar masses, likely through the collapse of massive early gas clouds.
Research Report:A mature quasar at cosmic dawn revealed by JWST rest-frame infrared spectroscopy
Related Links
Max Planck Institute for Astronomy, Heidelberg
Understanding Time and Space
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