It’s an exciting time in astronomy today, where records are being broken and reset regularly. We are barely two months into 2023, and already new records have been set for the farthest black hole yet observed, the brightest supernova, and the highest-energy gamma rays from our Sun. Most recently, an international team of astronomers using the ESO’s Very Large Telescope in Chile reportedly saw the brightest object ever observed in the Universe: a quasar (J0529-4351) located about 12 billion light years away that has the fastest-growing supermassive black hole (SMBH) at its center.
The international team responsible for the discovery consisted of astrophysicists from the Research School of Astronomy and Astrophysics (RSAA) and the Center for Gravitational Astrophysics (CGA) at the Australian National University (ANU). They were joined by researchers from the University of Melbourne, the Paris Institute of Astrophysics (IAP), and the European Southern Observatory (ESO). The paper that describes their findings, titled “The accretion of a solar mass per day by a 17-billion solar mass black hole,” recently appeared online and will published in the journal Nature Astronomy.
First observed in 1963 by Dutch-American astronomer Maarten Schmidt, quasars (short for “quasi-stellar objects”) are the bright cores of galaxies powered by SMBHs. These black holes collect matter from their surroundings and accelerate it to near the speed of light, which releases tremendous amounts of energy across the electromagnetic spectrum. Quasars become so bright that their cores will outshine all the stars in their disk, making them the brightest objects in the sky and visible from billions of light-years away.
As a general rule, astronomers gauge the growth rate of SMBHs based on the luminosity of their galaxy’s core region – the brighter the quasar, the faster the black hole is accreting matter. In this case, the SMBH at the core of J0529-4351 is growing by the equivalent of one Solar mass a day, making it the fastest-growing black hole yet observed. In the process, the accretion disk alone releases a radiative energy of 2 × 1041 Watts, more than 500 trillion times the luminous energy emitted by the Sun. Christian Wolf, an ANU astronomer and lead author of the study, characterized the discovery in a recent ESO press release:
“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. Personally, I simply like the chase. 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.”