Giant jets spied the black hole in the early universe

Astronomers have discovered evidence for an extraordinarily long ray of particles from a supermassive black hole in the early universe using NASA’s Chandra X-ray Observatory.

If confirmed, it is the farthest super-massive black hole with a ray detected in X-rays, coming from a galaxy about 12.7 billion light-years from Earth. It may help to explain how the largest black holes formed at a very early time in the universe’s history.

The source of the jet is a quasar – a fast-growing supermassive black hole – called PSO J352.4034-15.3373 (PJ352-15 for short), which sits in the center of a young galaxy. It is one of the two most powerful quasars detected in radio waves in the first billion years after the big bang, and is about a billion times more massive than the sun.

How can supermassive black holes grow so fast to reach such an enormous mass in this early era of the universe? This is one of the most important questions in astronomy today.

Despite their powerful seriousness and fearsome reputation, black holes do not necessarily attract everything that comes close to them. Material orbiting a black hole in a disk must lose speed and energy before it can fall further inward to cross the so-called event horizon, the point of no return. Magnetic fields can cause a braking effect on the disk as it drives a jet, which is one of the most important ways to lose material on the disk and thus increase the growth rate of black holes.

“If a playground moves too fast, it is difficult for a child to move to the center, so someone or something has to slow down the ride,” said Thomas Connor of the Jet Propulsion Laboratory (JPL) at NASA in Pasadena. , California, who led the study. “Around supermassive black holes, we think rays can take away enough energy so that material can fall inward and the black hole can grow.”

Astronomers had to observe PJ352-15 for a total of three days using Chandra’s sharp vision to find evidence for the X-ray. X-rays emitted about 160,000 light-years from the quasar were detected in the same direction as much shorter rays seen in radio waves. By comparison, the entire Milky Way spans about 100,000 light-years.

PJ352-15 breaks a few different astronomical records. First, the longest ray previously observed from the first billion years after the Big Bang was only about 5,000 light-years long, which is consistent with the radio observations of PJ352-15. Second, PJ352-15 is about 300 million light-years away from the farthest recorded X-ray.

“The length of this ray is significant because it means that the supermassive black hole that drives it has been growing for some time,” said co-author Eduardo Bañados of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. “This result highlights how X-ray studies of distant quasars provide a critical way to study the growth of the most supermassive black holes.”

The light detected by this ray was emitted when the universe was only 0.98 billion years old, less than a tenth of its current age. At this point, the intensity of the cosmic microwave background radiation (CMB) left over from the Big Bang was far greater than it is today.

As the electrons in the beam fly near the speed of light from the black hole, they move through and collide with photons that form the CMB radiation, which increases the energy of the photons into the X-ray range that can be detected by Chandra . In this scenario, the X-rays are significantly amplified in brightness compared to radio waves. This is consistent with the remark that the large X-ray function has no radio emission.

“Our result shows that X-ray observations may be one of the best ways to study quasars with jets in the early Universe,” said co-author Daniel Stern, also of JPL. “Or put another way, X-ray observations in the future could be the key to unlocking the secrets of our cosmic past.”

A paper describing these results has been accepted for publication in The Astrophysical Journal.