Brightest Object in the Universe Discovered – Powered by Supermassive Black Hole Eating a Sun a Day

This artist’s impression shows the record-breaking quasar J059-4351, the bright core of a distant galaxy that is powered by a supermassive black hole. Using ESO’s Very Large Telescope (VLT) in Chile, this quasar has been found to be the most luminous object known in the Universe to date. The supermassive black hole, seen here pulling in surrounding matter, has a mass 17 billion times that of the Sun and is growing in mass by the equivalent of another Sun per day, making it the fastest-growing black hole ever known. Credit: ESO/M. Kornmesser

Astronomers using the ESO’s VLT have discovered the brightest and most luminous quasar ever observed, powered by the fastest-growing black hole known, which accumulates mass at the rate of one Sun per day.

Using the European Southern Observatory’s (ESO) Very Large Telescope (VLT), astronomers have characterized a bright quasar, finding it to be not only the brightest of its kind, but also the most luminous object ever observed. Quasars are the bright cores of distant galaxies and they are powered by supermassive black holes. The black hole in this record-breaking quasar is growing in mass by the equivalent of one Sun per day, making it the fastest-growing black hole to date.

The black holes powering quasars collect matter from their surroundings in a process so energetic that it emits vast amounts of light. So much so that quasars are some of the brightest objects in our sky, meaning even distant ones are visible from Earth. As a general rule, the most luminous quasars indicate the fastest-growing supermassive black holes.

Astronomers have characterized the most luminous quasar observed to date, which is powered by the fastest-growing black hole. This black hole is growing in mass by the equivalent of one Sun per day. The matter being pulled in toward this black hole forms a disc that measures seven light-years in diameter — about 15,000 times the distance from the Sun to the orbit of Neptune. Credit: ESO

“We have discovered the fastest-growing black hole known to date. It has a mass of 17 billion Suns, and eats just over a Sun per day. This makes it the most luminous object in the known Universe,” says Christian Wolf, an astronomer at the Australian National University (ANU) and lead author of the study published today in Nature Astronomy. The quasar, called J0529-4351, is so far away from Earth that its light took over 12 billion years to reach us.

The matter being pulled in toward this black hole, in the form of a disc, emits so much energy that J0529-4351 is over 500 trillion times more luminous than the Sun.^[1] “All this light comes from a hot accretion disc that measures seven light-years in diameter — this must be the largest accretion disc in the Universe,” says ANU PhD student and co-author Samuel Lai. Seven light-years is about 15,000 times the distance from the Sun to the orbit of Neptune.

This image shows the region of the sky in which the record-breaking quasar J0529-4351 is situated. Using ESO’s Very Large Telescope (VLT) in Chile, this quasar has been found to be the most luminous object known in the Universe to date. This picture was created from images forming part of the Digitized Sky Survey 2, while the inset shows the location of the quasar in an image from the Dark Energy Survey. Credit: ESO/Digitized Sky Survey 2/Dark Energy Survey

And, remarkably, this record-breaking quasar was hiding in plain sight. “It is a surprise that it has remained unknown until today, when we already know about a million less impressive quasars. It has literally been staring us in the face until now,” says co-author Christopher Onken, an astronomer at ANU. He added that this object showed up in images from the ESO Schmidt Southern Sky Survey dating back to 1980, but it was not recognized as a quasar until decades later.

Finding quasars requires precise observational data from large areas of the sky. The resulting datasets are so large that researchers often use machine-learning models to analyze them and tell quasars apart from other celestial objects. However, these models are trained on existing data, which limits the potential candidates to objects similar to those already known. If a new quasar is more luminous than any other previously observed, the program might reject it and classify it instead as a star not too distant from Earth.

This artist’s impression shows the quasar J0529-4351, the bright core of a distant galaxy that is powered by a supermassive black hole. Credit: ESO/M. Kornmesser

An automated analysis of data from the European Space Agency’s Gaia satellite passed over J0529-4351 for being too bright to be a quasar, suggesting it to be a star instead. The researchers identified it as a distant quasar last year using observations from the ANU 2.3-meter telescope at the Siding Spring Observatory in Australia. Discovering that it was the most luminous quasar ever observed, however, required a larger telescope and measurements from a more precise instrument. The X-shooter spectrograph on ESO’s VLT in the Chilean Atacama Desert provided the crucial data.

The fastest-growing black hole ever observed will also be a perfect target for the GRAVITY+ upgrade on ESO’s VLT Interferometer (VLTI), which is designed to accurately measure the mass of black holes, including those far away from Earth. Additionally, ESO’s Extremely Large Telescope (ELT), a 39-metre telescope under construction in the Chilean Atacama Desert, will make identifying and characterizing such elusive objects even more feasible.

This video takes us on a journey from our Milky Way far into the sky to the quasar J0529-4351, the bright core of a distant galaxy, in the direction of the Pictor constellation. The video ends with an artist’s impression of this record-breaking object; all other visuals shown are real astronomical images. Credit: ESO/N. Risinger (skysurvey.org)/Digitized Sky Survey 2/Dark Energy Survey/M. Kornmesser. Music: Astral Electronic

Finding and studying distant supermassive black holes could shed light on some of the mysteries of the early Universe, including how they and their host galaxies formed and evolved. But that’s not the only reason why Wolf searches for them. “Personally, I simply like the chase,” he says. “For a few minutes a day, I get to feel like a child again, playing treasure hunt, and now I bring everything to the table that I have learned since.”

Notes

1. A few years ago, NASA and the European Space Agency reported that the Hubble Space Telescope had discovered a quasar, J043947.08+163415.7, as bright as 600 trillion Suns. However, that quasar’s brightness was magnified by a ‘lensing’ galaxy, located between us and the distant quasar. The actual luminosity of J043947.08+163415.7 is estimated to be equivalent to about 11 trillion Suns (1 trillion is a million million: 1,000,000,000,000 or 10¹²).

Reference: “The accretion of a solar mass per day by a 17-billion solar mass black hole” by Christian Wolf, Samuel Lai, Christopher A. Onken, Neelesh Amrutha, Fuyan Bian, Wei Jeat Hon, Patrick Tisserand and Rachel L. Webster, 19 February 2024, Nature Astronomy.
DOI: 10.1038/s41550-024-02195-x

The team is composed of Christian Wolf (Research School of Astronomy and Astrophysics, Australian National University, Australia [ANU] and Centre for Gravitational Astrophysics, Australian National University, Australia [CGA]), Samuel Lai (ANU), Christopher A. Onken (ANU), Neelesh Amrutha (ANU), Fuyan Bian (European Southern Observatory, Chile), Wei Jeat Hon (School of Physics, University of Melbourne, Australia [Melbourne]), Patrick Tisserand (Sorbonne Universités, CNRS, UMR 7095, Institut d’Astrophysique de Paris, France), and Rachel L. Webster (Melbourne).