Unprecedented Quasar Illuminates Cosmic Enigmas: The Most Luminous in 9 Billion Years

Representation of a quasar. Image Credit: Artist illustration: NOIRLab/NSF/AURA/J. da Silva

In the past 9 billion years of the cosmos’ history, researchers have detected the X-ray emissions from the most radiant quasar ever observed. This quasar, referred to as SMSS J114447.77-430859.3, or J1144 for brevity, provides fresh understanding about quasars’ internal operations and their interaction with the encompassing universe. The team’s discoveries have been published in the Monthly Notices of the Royal Astronomical Society.

Located in a galaxy around 9.6 billion light years from Earth, between the Centaurus and Hydra constellations, J1144 boasts incredible brightness, outshining the sun by a factor of 100,000 billion. Its relative closeness to Earth, compared to similar luminous entities, has given astronomers a unique chance to learn about the black hole driving the quasar and the surrounding space.

The study was spearheaded by Dr. Elias Kammoun, a postdoctoral fellow at the Research Institute in Astrophysics and Planetology (IRAP), and Zsofi Igo, a doctoral candidate at the Max Planck Institute for Extraterrestrial Physics (MPE).

Quasars, some of the brightest and most distant objects in the observable universe, are energized by the gravitational collapse of gas into a supermassive black hole. They are highly luminous active galactic nuclei (AGN) emitting significant electromagnetic radiation across radio, infrared, visible, ultraviolet, and X-ray spectra. J1144 was first spotted in visible wavelengths in 2022 by the SkyMapper Southern Survey (SMSS).

For this research, the team blended observations from multiple space-based observatories: the eROSITA instrument on the Spectrum-Roentgen-Gamma (SRG) observatory, the ESA XMM-Newton observatory, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), and NASA’s Neil Gehrels Swift observatory.

The group utilized the data from these observatories to ascertain the temperature of the X-rays radiated from the quasar. They discovered the temperature to be around 350 million Kelvin, surpassing the Sun’s surface temperature over 60,000 times. They also deduced that the mass of the black hole at the heart of the quasar is roughly 10 billion times that of the Sun, with its growth rate estimated at about 100 solar masses annually.

The X-ray light from this quasar fluctuated over a few days, which is unusual for quasars with black holes as substantial as J1144’s. The expected variability period for a black hole of this size is typically months or even years. The observations additionally highlighted that while some gas is consumed by the black hole, some is expelled in the form of powerful winds, introducing vast amounts of energy into the host galaxy.

Dr. Kammoun, the paper’s lead author, expressed his surprise that “no previous X-ray observatory has ever detected this source despite its remarkable potency.”

He further explained, “We typically find similar quasars at much larger distances, making them appear dimmer, and we perceive them as they existed when the Universe was only 2-3 billion years old. J1144 is an exceptional source as it is tremendously luminous and considerably closer to Earth (though still extraordinarily distant!), offering us a rare view of what such powerful quasars look like.”

“A new observational campaign for this source will commence in June this year, which may unveil more unexpected discoveries from this singular source.”

Reference: “The first X-ray look at SMSS J114447.77-430859.3: the most luminous quasar in the last 9 Gyr” by E S Kammoun, Z Igo, J M Miller, A C Fabian, M T Reynolds, A Merloni, D Barret, E Nardini, P O Petrucci, E Piconcelli, S Barnier, J Buchner, T Dwelly, I Grotova, M Krumpe, T Liu, K Nandra, A Rau, M Salvato, T Urrutia and J Wolf, 3 April 2023, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stad952

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More about Quasar J1144

• Research Institute in Astrophysics and Planetology (IRAP)
• Max Planck Institute for Extraterrestrial Physics (MPE)
• eROSITA on the Spectrum-Roentgen-Gamma (SRG) observatory
• ESA XMM-Newton observatory
• NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR)
• NASA’s Neil Gehrels Swift observatory
• Monthly Notices of the Royal Astronomical Society
• The first X-ray look at SMSS J114447.77-430859.3: the most luminous quasar in the last 9 Gyr