The fall of gas into a supermassive black hole propels quasars among the brightest and most distant objects in the known universe. They can be thought of as very bright active galactic nuclei (AGN) that produce massive amounts of electromagnetic radiation that can be observed at wavelengths in the radio, infrared, visible, ultraviolet, and X-ray ranges.
The most luminous quasar in the past 9 billion years of cosmic history, SMSS J114447.77-430859.3, or J1144 for short, has been observed to emit X-rays. The new perspective clarifies the inner workings and interactions of quasars with their environment.
Located between the constellations Centaurus and Hydra and hosted by a galaxy 9.6 billion light-years from Earth, J1144 is incredibly powerful and glows 100,000 billion times brighter than the sun. Astronomers can learn more about the quasar’s black hole and its surroundings thanks to J1144’s proximity to Earth compared to other objects of similar intensity.
For this study, researchers combined data from several space-based observatories, including NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), ESA’s XMM-Newton observatory, the Spectrum-Roentgen-Gamma (SRG) observatory’s eROSITA instrument, and NASA’s Neil Gehrel’s Swift Observatory. .
The scientists measured the temperature of the X-rays emanating from the quasar using the data from the four observatories. They found that this temperature was nearly 350 million Kelvin, which is more than 60,000 times hotter than the temperature on the sun’s surface. The scientists also found that the black hole at the center of the quasar has a mass about 10 billion times that of the sun and is expanding at about 100 solar masses per year.
This source produced X-rays that changed over a few days, which is unusual for quasars with black holes the size of those in J1144. For a black hole of this size, the normal timescale of variability would be on the order of months or even years. The observations also revealed that while the black hole sucks up some of the gas, some is released by strong winds that release a significant amount of energy to the host galaxy.
Dr. Kammoun, lead author of the article, says: “We were very surprised that no previous X-ray observatory has ever observed this source, despite its extreme power.”
He adds, “Similar quasars are usually found at much greater distances, so they appear much fainter, and we see them as they were when the universe was only 2-3 billion years old. J1144 is a rare source because it is so bright and much more dense near Earth (although still at an enormous distance!), giving us a unique glimpse of what such powerful quasars look like.”
“A new monitoring campaign of this source will start in June this year, which may reveal more surprises from this unique source.”
- ES Kammoun et al., The first X-ray of SMSS J114447.77-430859.3: the most luminous quasar in the last 9 Gyr, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad952