When the iconic black hole the size of our Solar System located at the center of the galaxy M87 was imaged in 2019, astronomers described it as witnessing the “gates of Hell and the end of spacetime.” Fast forward to today, astronomers using three Maunakea Observatories in Hawai’i describe the second-most distant quasar ever found at a cosmological redshift greater than 7.5, and it hosts a black hole twice as large as the other quasar known in the same era. They call this new quasar Pōniuā`ena, which means “unseen spinning source of creation, surrounded with brilliance” in the Hawaiian language. The light observed from Pōniuā`ena reached Earth 13 billion years after leaving the quasar just 700 million years after the Big Bang.
Its Existence –A Big Challenge for Current Theory
“How can the universe produce such a massive black hole so early in its history?” said Xiaohui Fan, Regents’ professor and associate department head of the Department of Astronomy at the University of Arizona. Current theory holds that the growth of the first giant black holes started during the Epoch of Reionization, beginning about 400 million years after the Big Bang. “This discovery presents the biggest challenge yet for the theory of black hole formation and growth in the early universe.”
Most Massive, Second Most Distant
Astronomers discovered the most distant quasar (named J1342+0928) in 2018 and now the second-most distant, Pōniuā`ena (or J1007+2115, at redshift 7.515). Spectroscopic observations from Keck Observatory and Gemini Observatory show the supermassive black hole powering Pōniuā`ena is 1.5 billion times more massive than our Sun.
Pōniuā`ena is the most distant object known in the universe hosting a black hole exceeding one billion solar masses,” said Jinyi Yang, a postdoctoral research associate at the Steward Observatory of the University of Arizona and lead author of the study.
Started as a Cosmic “Seed”
For a black hole of this size to form this early in the universe, it would need to start as a 10,000 solar mass “seed” black hole about 100 million years after the Big Bang, rather than growing from a much smaller black hole formed by the collapse of a single star. Pōniuā`ena has placed new and important constraints on the evolution of the matter between galaxies (intergalactic medium) in the reionization epoch.
A Cosmic Lighthouse
“Pōniuā`ena acts like a cosmic lighthouse. As its light travels the long journey towards Earth, its spectrum is altered by diffuse gas in the intergalactic medium which allowed us to pinpoint when the Epoch of Reionization occurred,” said co-author Joseph Hennawi, a professor in the Department of Physics at the University of California, Santa Barbara.
Yang’s team first detected Pōniuā`ena as a possible quasar after combing through large area surveys such as the UKIRT Hemisphere Survey and data from the University of Hawai’i Institute for Astronomy’s Pan-STARRS1 telescope on the Island of Maui.
Revealed by the Gemini Observatory
In 2019, the researchers observed the object using Gemini Observatory’s GNIRS instrument as well as Keck Observatory’s Near Infrared Echellette Spectrograph (NIRES) to confirm the existence of Pōniuā`ena.
“The preliminary data from Gemini suggested this was likely to be an important discovery. Our team had observing time scheduled at Keck just a few weeks later, perfectly timed to observe the new quasar using Keck’s NIRES spectrograph in order to confirm its extremely high redshift and measure the mass of its black hole,” said co-author Aaron Barth, a professor in the Department of Physics and Astronomy at the University of California, Irvine.
“We recognize there are different ways of knowing the universe,” said John O’Meara, chief scientist at Keck Observatory. “Pōniuā`ena is a wonderful example of interconnectedness between science and culture, with shared appreciation for how different knowledge systems enrich each other.”
The Keck astronomers “recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.”
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