Black holes formed quasars less than a billion years after the Big Bang

Supermassive black holes appear to be present at the center of every galaxy, dating back to some of the oldest galaxies in the Universe. And we have no idea how they got there. It shouldn’t be possible for them to grow from supernova remnants to supermassive sizes as quickly as they do. And we don’t know of any other mechanism that can form something large enough that extreme growth isn’t necessary.

The apparent impossibility of supermassive black holes existing in the early Universe was already a problem; The James Webb Space Telescope has only made things worse by finding older and older cases of galaxies with supermassive black holes. In the latest example, researchers have used Webb to characterize a quasar driven by a supermassive black hole as it existed approximately 750 million years after the Big Bang. And it seems surprisingly normal.

Looking back in time

Quasars are the brightest objects in the Universe and operate thanks to the active feeding of supermassive black holes. The surrounding galaxy feeds them enough material to form bright accretion disks and powerful jets, which emit copious amounts of radiation. They are often partially enveloped in dust, which glows by absorbing some of the energy emitted by the black hole. These quasars emit so much radiation that they ultimately completely expel some of the nearby material from the galaxy.

So the presence of these features in the early Universe would tell us that supermassive black holes were not only present in the early Universe but were also embedded in galaxies as they are in more recent times. But it has been very difficult to study them. To begin with, we haven’t identified many; There are only nine quasars that date back to before the Universe was 800 million years old. Because of that distance, features are difficult to resolve, and the redshift caused by the expansion of the Universe takes the intense ultraviolet radiation from many elements and extends them deep into the infrared.

However, the Webb telescope was designed specifically to detect objects in the early Universe by being sensitive to the infrared wavelengths where this radiation appears. So the new research is based on pointing the Webb to the first of those nine early quasars discovered, J1120+0641.

And it seems…remarkably normal. Or at least very similar to quasars from more recent periods in the history of the Universe.

Mostly normal

The researchers analyze the continuity of the radiation produced by the quasar and find clear indications that it is embedded in a donut of hot, dusty material, as seen in later quasars. This dust is slightly hotter than in some more recent quasars, but that appears to be a common feature of these objects earlier in the history of the Universe. Radiation from an accretion disk is also evident in the emission spectrum.

Various means to estimate black hole mass produced values ​​in the area of ​​109 times the mass of the Sun, clearly placing it in supermassive black hole territory. There is also evidence, from a slight blueshift in some of the radiation, that the quasar is ejecting material at about 350 kilometers per second.

There are a couple of oddities. One is that the material also appears to fall inward at about 300 kilometers per second. This could be because the material moves away from us in the accretion disk. But if so, it should match the material spinning toward us on the opposite side of the disk. This has been observed several times in early quasars, but the researchers admit that “The physical origin of this effect is unknown.”

One option they suggest as an explanation is that the entire quasar is moving, knocked out of its position at the center of the galaxy by a previous merger with another supermassive black hole.

The other oddity is that there is also a very rapid outflow of highly ionized carbon, moving at about twice the speed of quasars at later times. This has been seen before, but there is no explanation for it either.

How did this happen?

Despite its rarities, this object closely resembles quasars from more recent times: “Our observations demonstrate that the complex structures of the dust torus and the [accretion disk] can be established around a [supermassive black hole] “less than 760 million years after the Big Bang.”

And again, that is a problem since it indicates the presence of a supermassive black hole integrated into its host galaxy at a very early stage in the history of the Universe. To reach the kind of sizes seen here, black holes push what is called the Eddington limit: the amount of material they can absorb before the radiation produced by doing so expels neighboring material, choking off the black hole’s food supply. black hole.

That suggests two options. One is that these things ingested material well beyond the Eddington limit for most of its history, something we haven’t observed and is definitely not true for this quasar. The other option is for them to start en masse (around 104 times the mass of the Sun) and continued to feed at a more reasonable rate. But we don’t really know how something so big can form.

So the early Universe remains a rather puzzling place.

Nature Astronomy, 2024. DOI: 10.1038/s41550-024-02273-0 (About DOIs).

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