After more than a decade of searching for the first quasars, an international team of astronomers led by researchers from the University of Arizona, used the National Science Foundation’s (NSF) NOIRLab’s Gemini Observatory and Cerro Tololo Inter-American Observatory (CTIO) to discover the most massive quasar known in the early Universe — detected from a time only 700 million years after the Big Bang. Quasars are the most energetic objects in the Universe, powered by their supermassive black holes, and since their discovery astronomers have been keen to determine when they first appeared in our cosmic history.
Systematic searches for these objects have led to the discovery of the most distant quasar (J1342+0928) in 2018 and now the second most distant, J1007+2115. The A Hua He Inoa program named J1007+2115 Pōniuāʻena, meaning “unseen spinning source of creation, surrounded with brilliance" in the Hawaiian language. The supermassive black hole powering Pōniuāʻena is 1.5 billion times more massive than our Sun.
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.
Current theory suggests that at the beginning of the Universe following the Big Bang, atoms were too distant from one another to interact and form stars and galaxies. The birth of stars and galaxies as we know them happened during the Epoch of Reionization, beginning about 400 hundred million years after the Big Bang. The discovery of quasars like Pōniuāʻena, deep into the reionization epoch, is a big step towards understanding this process of reionization and the formation of early supermassive black holes and massive galaxies. Pōniuāʻena has placed new and important constraints on the evolution of the matter between galaxies (the intergalactic medium) in the reionization epoch.
The first clue to discovering Pōniuāʻena was uncovered using the Dark Energy Camera (DECam) on the Víctor M. Blanco 4-meter Telescope, located at CTIO in Chile. The team uncovered a possible quasar in the data, and in 2019 they observed it with telescopes including the Gemini North telescope and the W. M. Keck Observatory both on Maunakea on Hawai‘i Island. Gemini’s GNIRS instrument confirmed the existence of Pōniuāʻena.
In honor of its discovery from Maunakea, this quasar was given the Hawaiian name Pōniuāʻena. The name was created by thirty Hawaiian immersion school teachers during a workshop led by the A Hua He Inoa group, a Hawaiian naming program led by the ‘Imiloa Astronomy Center of Hawai‘i. Pōniuāʻena is the first quasar to receive an indigenous name.
While the discovery of Pōniuāʻena is hugely significant and exciting, the search for distant quasars began with the research team conducting large area surveys. Astronomer Jiangtao Li, an assistant research scientist with the University of Michigan Astronomy Department, is a part of the team that has been hunting for quasars in the early Universe through these large area surveys. Li and his colleagues begin with optical/IR surveys to select high-z quasar candidates, then conduct multi-wavelength follow-up observations to confirm the nature of the candidates and further study some related objects (e.g., galaxies, proto-clusters, inter-galactic medium, etc.).
Li has been contributing to this project mostly through X-ray observations of high-z quasars and conducting follow-up observations of objects using the Magellan telescope at Las Campanas Observatory, to which University of Michigan has privileged access. Magellan is one of the most powerful optical and infrared ground-based telescopes, making it well-suited to the search for quasars and other objects in the early Universe.
“University of Michigan's partnership in the world class telescopes, such as the twin 6.5m Magellan telescopes, will provide its researchers and students a lot of unique opportunities to study the growth of supermassive black holes and many other interesting objects in the early Universe, like Pōniuāʻena,” said Li. “These studies will play a critical role in our understanding of the formation and evolution of supermassive black holes, galaxies, and larger scale structures over the cosmic time.”
Link to original press release: NSF's NOIRLab
U-M Astronomy Contact: Jiangtao Li