A monster quasar in the early universe
Although quasars are found over a range of distances, most are exceedingly far away. The very distant quasars exist at a time shortly after the Big Bang, when our universe was young. Our current understanding of quasars is that they lie in the centers of young, active galaxies. The luminous, powerful and energetic quasars are thought to be driven by a process of accretion onto supermassive black holes. This week, astronomers announced the discovery of the most massive quasar yet known in the early universe. Its monster central black hole has a mass equivalent to 1.5 billion of our suns. By contrast, the quiescent and relatively sedate black hole at the heart of our Milky Way galaxy has a mass of only 4 million suns. In honor of the new quasar’s discovery via telescopes at the summit of Mauna Kea, the quasar has been given the Hawaiian name Poniua’ena, which means:
… unseen spinning source of creation, surrounded with brilliance.
The newly discovered quasar is formally designated J1007+2115. It’s the first quasar to receive an Indigenous name, created by 30 Hawaiian immersion school teachers during a workshop led by the A Hua He Inoa group, part of the ‘Imiloa Astronomy Center – an astronomy and culture education center – in Hilo, Hawaii.
The quasar’s brilliance suggests its monstrously massive central black hole. Consider our Milky Way’s 4 million solar mass black hole again, in contrast to Poniua’ena’s 1.5 billion solar mass black hole. Consider that a million seconds is about 12 days, while a billion seconds is 31 years. So you can see, perhaps, that this distant quasar and its black hole are truly colossal.
Poniua’ena is one of only two quasars known from the same early period in our universe’s history. The statement from the University of Arizona, whose astronomers led the discovery, explained:
The supermassive black hole powering Poniua’ena makes this quasar the most distant, and therefore earliest, object known in the universe to host a black hole exceeding 1 billion solar masses. According to a new study documenting the quasar’s discovery, the light from Poniua’ena took 13.02 billion years to reach Earth – starting its journey just 700 million years after the Big Bang.
A scientific description of the discovery is available now via arXiv and will be published in the peer-reviewed Astrophysical Journal Letters. The study introduces a mystery about this quasar, which is … how could such a massive black hole have formed at such an early time in the history of our universe? Lead author Jinyi Yang of Steward Observatory at University of Arizona said:
It’s the earliest monster of this kind that we know of. The time was too short for it to grow from a small black hole to the enormous size we see.
Co-author Xiaohui Fan, also of Steward Observatory, said:
This discovery presents the biggest challenge yet for the theory of black hole formation and growth in the early universe.
Their statement explained:
The notion that a black hole of Poniua’ena 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 next to impossible, according to current cosmological models.
Instead, the study authors suggest that the quasar would have had to start out as a ‘seed’ black hole already containing the equivalent mass of 10,000 suns as early as 100 million years after the Big Bang.
The discovery of a quasar from the dawn of the cosmos provides researchers with a rare glimpse into 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, 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, about 400 million years after the Big Bang. Fan said:
In the aftermath of the Big Bang, the universe was very cold, because there were no stars yet; no light. It took about 300 to 400 million years for the first stars and galaxies to appear, and they began heating up the universe.
Their statement further explained:
Under the influence of heating, hydrogen molecules were stripped of electrons in a process known as ionization. This process lasted only a few hundred million years – a blink of an eye in the life of the universe – and is the subject of ongoing research.
The discovery of quasars like Poniua’ena, deep into the reionization epoch, is a big step towards understanding the process of reionization and the formation of early supermassive black holes and massive galaxies. Poniua’ena has placed new and important constraints on the evolution of the matter between galaxies, known as the intergalactic medium, during the reionization epoch.
This quasar looks like it was detected right at the mid-point of that period, and the fact that we can observe these objects helps us refine what happened during that period.
Bottom line: Astronomers just announced the discovery of the most massive quasar yet known in the early universe. Its monster central black hole has a mass equivalent to 1.5 billion of our suns. The object has been given the Hawaiian name Poniua’ena.