By Leah Poffenberger
Artist’s representation of Pōniuāʻena. IMAGE CREDIT: International Gemini Observatory/NOIRLab/NSF/AURA/P. Marenfeld
Looking up at the night sky stars is a bit like going to a history museum: The light we see is giving us a glimpse into the past. When light is emitted from a star, it has to travel across the galaxy at 186,000 miles per second—or lightspeed—before it reaches us here on Earth. Depending on how far away a star is from us, its light might have to travel anywhere from four years (as is the case for the star in our closest neighboring solar system) to billions of years. The lights we see twinkling in the night sky are actually snapshots of the star as it was years in the past.
When astronomers discover new objects in space, the further away from Earth they are, the longer back in the Universe they allow us to study. And recently, they’ve discovered the second most distant quasar—a bright center of an ancient galaxy—ever detected. Light from this quasar traveled 13 billion years, giving researchers a glimpse into an early era of the Universe. This newly discovered quasar was given the name Pōniuāʻena, meaning “unseen spinning source of creation, surrounded with brilliance” in the indigenous language of Hawai’i.
Pōniuāʻena was first detected using the Cerro Tololo Inter-American Observatory (CTIO) in Chile and subsequently observed with telescopes located on Maunakea on Hawai’I Island: the Gemini North telescope and the W. M. Keck Observatory.
The term “quasar” was coined in the 1960s as a short-hand for “quasi-stellar radio sources”—objects in the galaxy that can look like far-away stars but were first detected by their emission of radio waves. Quasars, the most energetic objects in the universe, can look like stars at a distance, thanks to luminous gasses swirling around the quasar’s engine: a supermassive black hole, millions to billions of times more massive than the sun. The black hole at the center of Pōniuāʻena is 1.5 billion times the mass of the sun.
“Pōniuāʻena 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 a lead scientist on the project.
Pōniuāʻena’s black hole is nearly double the mass of the black hole at the center of the most distant quasar ever detected—that black hole had a mass of 800 million suns. The discovery of both of these supermassive black holes have challenged existing theories of how black holes and galaxies formed in the early universe.
“How can the Universe produce such a massive black hole so early in its history?” asks Xiaohui Fan, Regents’ professor and associate department head of the Department of Astronomy at the University of Arizona. “This discovery presents the biggest challenge yet for the theory of black hole formation and growth in the early Universe.”
Since the light from Pōniuāʻena takes so long to reach Earth, astronomers observing the quasar are seeing it as it was only 700 million years after the Big Bang, right in the middle of a period of the Universe that gave birth to stars and galaxies. The discovery of Pōniuāʻena can help guide further understanding of how supermassive black holes and massive galaxies formed in the early universe.
The immense size of Pōniuāʻena’s black hole existing so early in the universe has already challenged ideas of how black holes form. To reach 1.5 billion solar masses only 700 million years after the Big Bang, Pōniuāʻena couldn’t have grown from a black hole created by a single star collapsing—it would’ve need to form from a 10,000 solar mass black hole about 100 million years after the Big Bang, in the infancy of the Universe.
Caption: An artist’s representation of the seed black hole, 100 million years after the Big Bang. CREDIT: International Gemini Observatory/NOIRLab/NSF/AURA/P. Marenfeld
The quasar’s name, Pōniuāʻena (pronounced POH-knee-ew-aah-EH-na) was selected at a naming workshop led by the A Hua He Inoa group. A Hua He Inoa is a program created by the ‘Imiloa Astronomy Center of Hawai’i to connect traditional indigenous practices to the naming of astronomical discoveries. Pōniuāʻena is the first quasar to be named by A Hua He Inoa, but it joins other astronomical objects in receiving an indigenous Hawaiian name, such as ʻOumuamuam, the first interstellar object ever discovered.
“…It is exciting to see the collaboration of science and culture in local communities, highlighted by this new name,” said Chris Davis, Program Officer at the National Science Foundation, which operates the Gemini telescope and CTIO.
Thirty Hawaiian immersion school teachers attended A Hue He Inoa’s naming workshop to learn about the quasar’s discovery and select a fitting name.
“I am extremely grateful to be a part of this educational experience — it is a rare learning opportunity,” said Kauʻi Kaina, a High School Hawaiian Immersion Teacher from Kahuku, Oʻahu who was involved in the naming workshop. “Today it is relevant to apply these cultural values in order to further the wellbeing of the Hawaiian language beyond ordinary contexts, such as in school, but also so that the language lives throughout the Universe.”