Astronomers have discovered the most massive quasar known in the early universe, containing a monstrous black hole with a mass equivalent to 1.5 billion suns. Formally designated J1007 + 2115, the newly discovered quasar is one of only two known from the same cosmological period. Quasars are the most energetic objects in the universe, and since their discovery astronomers have been interested in determining when they first appeared in our cosmic history.
In honor of its discovery through telescopes on Maunakea, a mountain revered in Hawaiian culture, the quasar was given the Hawaiian name of Pōniuāʻena, meaning “invisible rotating source of creation, surrounded by brilliance.” It is the first quasar to receive an indigenous name, which was created by 30 Hawaiian immersion school teachers during a workshop led by the A Hua He Inoa group, a Hawaiian naming program run by the ‘Hawaiian Imiloa Astronomy Center’.
According to current theory, quasars are powered by supermassive black holes. As black holes swallow up surrounding matter, such as dust, gas, or even entire stars, they emit huge amounts of energy, resulting in luminosities known to eclipse entire galaxies.
The supermassive black hole that feeds Pōniuāʻena makes this quasar the most distant, and therefore the oldest, known object in the universe that houses a black hole that exceeds one billion solar masses. According to a new study documenting the discovery of the quasar, it took the light of Pōniuāʻena 13.02 billion years to reach Earth, beginning its journey just 700 million years after the Big Bang.
“It is the first monster of its kind that we know of,” said Jinyi Yang, a postdoctoral associate researcher at the Steward Observatory at the University of Arizona and lead author of the study, to be published in The Astrophysical charts. “The time was too short for it to grow from a small black hole to the enormous size we see.”
The question of how such a massive black hole could materialize when the universe was still in its infancy has plagued astronomers and cosmologists for a long time, said co-author Xiaohui Fan, professor of regents and associate chief of the UArizona Department of Astronomy.
“This discovery presents the greatest challenge to the theory of black hole formation and growth in the early universe,” said Fan.
The notion that a black hole of Pōniuāʻenas proportions could have evolved from a much smaller black hole formed by the collapse of a single star in such a short time since the Big Bang is almost impossible, according to current cosmological models.
Instead, the study authors suggest that the quasar would have had to start as a “seed” black hole that already contains the equivalent mass of 10,000 suns and 100 million years after the Big Bang.
A retrospective look at a young universe
Pōniuāʻena was discovered through a systematic search for the most distant quasars. It started with the research team reviewing large areas such as the DECaLS image survey, which uses the Dark Energy Chamber at the 4-meter Víctor M. Blanco Telescope located at the Cerro Tololo Inter-American Observatory in Chile, and the UHS survey images, which it uses the wide-field camera at the UK infrared telescope, located in Maunakea.
The team discovered a possible quasar in the data, and in 2019 observed it with telescopes, including the Gemini North Telescope and the WM Keck Observatory, both in Maunakea. The Magellan telescope at the Las Campanas Observatory in Chile confirmed the existence of Pōniuāʻena.
“The Gemini observations were critical in obtaining the high-quality near-infrared spectra that gave us the measurement of the amazing mass of the black hole,” said co-author Feige Wang, a member of NASA’s Hubble at the Steward Observatory.
The discovery of a quasar from the dawn of the cosmos provides researchers with a rare glimpse of a time when the universe was still young and very different from what we see today, the researchers said.
Current theory suggests that at the beginning of the universe, after the Big Bang, atoms were too distant from each other to interact and form stars and galaxies. The birth of stars and galaxies as we know them occurred during the Age of Reionization, some 400 million years after the Big Bang.
“After the Big Bang, the universe was very cold, because there were no stars yet; there was no light,” said Fan. “The first stars and galaxies appeared between 300 and 400 million years ago, and began to heat the universe.”
Under the influence of heating, the hydrogen molecules were stripped of electrons in a process known as ionization. This process lasted only a few hundred million years, the blink of an eye on the life of the universe, and is the subject of ongoing research.
The discovery of quasars like Pōniuāʻena, deep in the reionization era, is a great step towards understanding the reionization process and the formation of the first supermassive black holes and massive galaxies. Pōniuāʻena has placed important new constraints on the evolution of matter between galaxies, known as the intergalactic medium, during the reionization era.
“It appears that this quasar was detected right at the midpoint of that period,” Fan said, “and the fact that we can observe these objects helps us refine what happened during that period.”
In 2018, the survey team announced the discovery of the most distant quasar found to date. Designated as J1342 + 0928, that object is 2 million years older than Pōniuāʻena, a fairly insignificant difference by cosmic standards, according to Fan, who participated in both discoveries, which were made using the Gemini International Observatory and the Cerro Tololo Inter-American Observatory. —Both programs of the National Research Laboratory for Optical-Infrared Astronomy of the National Science Foundation.
“The 2 million light-year difference of 13 billion makes it pretty close to a tie,” Fan said.
Cosmic Tempest: Astronomers detect the greatest amount of energy flow from a distant quasar
“Poniua’ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole”, Jinyi Yang et al., 2020, to appear in Astrophysical charts arxiv.org/abs/2006.13452
Citation: Astronomers discover the ‘monster’ quasar of the early universe (2020, June 25) recovered on June 25, 2020 from https://phys.org/news/2020-06-astronomers-monster-quasar-early-universe .html
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