Discovery of distant blazars supports rapid black hole formation in the early universe

Astronomers have discovered a key piece of the puzzle of how supermassive black holes were able to grow so quickly in the early universe. It’s a special kind of active galactic nucleus so far away that it took more than 12.9 billion years for its light to reach us. This so-called blazer serves as a statistical marker. Its existence means that there are many similar but hidden objects, all of which should emit powerful jets of particles.

This is where this discovery becomes important for the evolution of the universe. It is thought that black holes with jets can grow much faster than those without jets. The research is published in a paper published in Nature Astronomy and in The Astrophysical Journal Letters.

Active galactic nuclei (AGNs) are the very bright centers of galaxies. The engine driving its enormous energy output is a supermassive black hole. The falling of matter into such black holes (accretion) is the most efficient mechanism known to physics in terms of releasing vast amounts of energy. This unparalleled efficiency is why AGNs can produce more light in a space smaller than our solar system than all the stars in hundreds, thousands, or even more galaxies.

At least 10% of all AGNs are thought to emit focused beams of high-energy particles known as jets. These jets are shot in two opposite directions from the immediate vicinity of the black hole and are sustained and guided by the magnetic field of the “accretion disk” of matter. This disk is formed by gas swirling around the black hole and falling into it. For us to see AGN as a Blazer, something very unlikely would have to happen. This means that our observation base, Earth, must be in just the right place for the AGN jet to head directly at us.

The result is an astronomical analogue of someone shining a very bright flashlight beam directly into your eyes: a particularly bright object in the sky. Blasers are also characterized by rapid changes in brightness over time scales of days, hours, or even shorter. This is the result of random variations in the swirling accretion disk at the base of the jet and instabilities in the interactions between the jets. Magnetic fields and charged particles.

Active galactic nucleus discovered in the early universe

This new discovery follows a systematic study of active galactic nuclei in the early universe, conducted by Eduardo Bañados, group leader at the Max Planck Institute for Astronomy, and an international team of astronomers, who specialize in the first billion years of cosmic history. This was the result of a thorough search. .

Because light takes time to reach us, we can see distant objects as they were millions or even billions of years ago. For more distant objects, the so-called cosmological redshift due to the expansion of the universe shifts their light to much longer wavelengths than the wavelength at which it was emitted. Bañados and his team took advantage of this fact to systematically identify objects that had previously been redshifted and invisible in normal visible light (in this case, the Dark Energy Legacy Survey), but were bright sources in radio surveys. I searched for it. (3 GHz VLASS survey).

Of the 20 candidates that met both criteria, only one, designated J0410-0139, met the additional criterion of exhibiting significant brightness fluctuations in the radio domain, indicating that it could be a buzzer. is increasing.

The researchers then used an unusually large array of telescopes, including near-infrared observations with ESO’s New Technology Telescope (NTT), spectra with ESO’s Very Large Telescope (VLT), and additional near-infrared spectra with LBT. I investigated further. With X-ray images from the Keck and Magellan telescopes, both ESA’s XMM-Newton Space Telescope and NASA’s Chandra Space Telescope, millimeter-wave observations from the ALMA and Noema arrays, and more detailed radio observations from the National Radio Astronomy Observatory’s VLA telescope. , the object’s status as an AGN, and in particular as a blazer, is confirmed.

The observations also yielded the distance of the AGN (via its redshift) and found traces of the host galaxy in which it is embedded. The light from that active galactic nucleus takes 12.9 billion years to reach us (z=6.9964), conveying information about the universe 12.9 billion years ago.

“Where there is one, there are a hundred more.”

According to Bañados, “The fact that J0410-0139 is a Blazer, a jet aircraft that just so happens to be aimed directly at Earth, has immediate statistical significance. As a real-life analogy, the Imagine reading an article about how many more people played that lottery and didn’t win that much money, considering how rare such winnings are in the lottery. You can immediately guess that it is different.

“Similarly, finding one AGN with a jet pointing directly at us means that at that time in the history of the universe there must have been many AGNs with jets pointing directly at us. It means no.”

To make a long story short, in the words of Silvia Berraditta, a postdoctoral fellow at MPIA and co-author of this book, “Where there’s one, there’s a hundred more.”

The light from the previous record holder for the most distant blazar took about 100 million years less time to reach us (z=6.1). An additional 100 million years may seem small given the fact that we are looking back more than 12 billion years, but it makes a crucial difference. We are now in a time when the universe is changing rapidly. Over the last 100 million years, the mass of a supermassive black hole could increase by an order of magnitude.

Based on current models, the number of AGNs should have increased 5-10 times over 100 million years. It would not be surprising to find out that such blazers existed 12.8 billion years ago. Discovering that such a blazar existed 12.9 billion years ago, as in this case, is another matter entirely.

Helping black holes grow for 12.9 billion years

The existence of a whole population of jet-equipped AGNs at that particular early time has important implications for the history of the universe and the growth of supermassive black holes in the centers of galaxies in general. Black holes with jets in the AGN can gain mass faster than black holes without jets.

Contrary to popular belief, it is difficult for gas to fall into a black hole. The natural behavior of gas is that as it approaches a black hole, it gains velocity and orbits the black hole, much like planets orbit around the sun (“conservation of angular momentum”). To enter, the gas must slow down and lose energy. The magnetic field associated with the particle jet can interact with the swirling disk of gas, providing such a “braking mechanism” and helping the gas fall.

This means that the results of the new discovery are likely to form the basis for future models of black hole growth in the early universe. These findings suggest that there were large numbers of active galactic nuclei with jets 12.9 billion years ago. There was an associated magnetic field that could help the black hole grow at a significant rate.