TON 618 Mass Estimate Falls to 40.7 Billion Suns From 66 Billion

Q: What has the cosmic titan TON 618, seen 10.8 billion years ago, become today?

No one knows exactly what TON 618 is today, because we only see it as it was 10.8 billion years ago. But the strongest scientific inference is that it is no longer the blazing quasar we observe in that ancient light and has likely evolved into the central black hole of a very massive, comparatively quiet galaxy. That view fits how quasars are understood to evolve. Hyperluminous quasars were far more common in the early universe, when black holes had abundant gas to consume. Over billions of years, that fuel supply is expected to diminish through accretion, star formation, and feedback that blows gas away. In that scenario, TON 618’s black hole would still exist, probably having grown somewhat through accretion and mergers, but its accretion disk would have faded dramatically, leaving a much less active galactic nucleus or even a dormant one. Its exact present-day mass is also uncertain. Published estimates range from about 40.7 billion to 66 billion solar masses, already placing it near proposed theoretical growth limits for non-spinning black holes. That suggests it may not have grown enormously since the epoch we are seeing, though it could have changed through mergers or slower accretion. So the best answer is that TON 618 has probably become a giant, mature galaxy hosting an ultramassive black hole that is far less conspicuous than the quasar seen in the ancient universe. Its black hole almost certainly survives; what has likely vanished is the spectacular quasar phase.

1 articles · Updated · spacedaily.com · Jun 11

Ge and colleagues’ 2019 reanalysis cut TON 618’s estimated black hole mass to about 40.7 billion solar masses, down sharply from the widely cited 66 billion figure from a 2004 study.
The revision stems from improved virial-mass methods using quasar emission-line data, a technique that infers mass from gas speeds but can vary by a factor of two because of assumptions about geometry and viewing angle.
Even at 40.7 billion solar masses, TON 618 remains among the largest black holes known: its event horizon would span roughly 1,600 AU in diameter, still vastly larger than the solar system’s planetary region.
The lower estimate also changes the comparison with the Milky Way, putting TON 618 at roughly two-thirds of our galaxy’s total stellar mass rather than exceeding it outright.
At about 10.8 billion light-years away, TON 618 remains a key test case for whether ultramassive black holes are nearing a theoretical growth ceiling of around 50 billion solar masses.

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spacedaily.com3d ago

TON 618's Mass Revised to 40.7 Billion Solar Masses by Ge et al.

What has the cosmic titan TON 618, seen 10.8 billion years ago, become today?

How did black holes become galactic monsters when the universe was still in its infancy?

Do giant black holes form first, with galaxies merely growing around them as an afterthought?

TON 618’s Mass Revisited: How New Science Is Redefining the Limits of Black Hole Size

Overview

TON 618 is an ultramassive black hole, recognized as one of the largest and most massive ever discovered. For many years, its mass was widely accepted to be about 66 billion times that of the Sun, a figure based on a 2004 analysis by Ohad Shemmer and colleagues. This estimate was calculated by studying the width of the Hβ emission line in TON 618’s spectrum. The immense scale of TON 618 places it among the so-called 'monster black holes,' and ongoing research continues to refine our understanding of its true mass and significance in the universe.

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spacedaily.com3d ago

TON 618's Mass Revised to 40.7 Billion Solar Masses by Ge et al.

TON 618 Mass Estimate Falls to 40.7 Billion Suns From 66 Billion

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TON 618’s Mass Revisited: How New Science Is Redefining the Limits of Black Hole Size

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