A gigantic jet spied from a black hole

Astronomers have discovered evidence of an extraordinarily long particle jet from a supermassive black hole at the start of the Universe, using NASA’s Chandra X-ray observatory.

If confirmed, it would be the farthest supermassive black hole with a jet detected in x-rays, originating in a galaxy about 12.7 billion light-years from Earth. This can help explain how the largest black holes formed very early in the history of the Universe.

The source of the jet is a quasar – a fast-growing supermassive black hole – named PSO J352.4034-15.3373 (PJ352-15 for short), which sits at 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 it is about a billion times more massive than the Sun.

How are supermassive black holes able to grow so quickly to reach such enormous mass at this early time in the Universe? This is one of the key questions in astronomy today.

Despite their powerful gravity and formidable reputation, black holes do not necessarily attract everyone who approaches them. Material orbiting a black hole in a disc needs to 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 disc when propelling a jet, which is a key way for the disc material to lose energy and therefore improve the rate of hole growth. black.

“If a playground merry-go-round is moving too fast, it is difficult for a child to move to the center, so someone or something has to slow down the race,” said Thomas Connor of the Jet Propulsion Laboratory (JPL) from NASA in Pasadena. , California, who led the study. “Around supermassive black holes, we believe that the jets can carry enough energy so that the material can fall inwards and the black hole can grow.”

Astronomers were to observe PJ352-15 for a total of three days using Chandra’s sharp vision to detect evidence of the X-ray jet. X-ray emission was detected about 160,000 light-years from the quasar in the same. direction than much shorter jets 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 jet observed before since the first billion years after the Big Bang was only about 5,000 light years, which corresponds to the radio observations of PJ352-15. Second, the PJ352-15 is about 300 million light years further away than the farthest X-ray jet recorded before it.

“The length of this jet is important because it means that the supermassive black hole that powers it has been developing for a considerable period of time,” said co-author Eduardo Bañados of the Max Planck Institute for Astronomy (MPIA ) in Heidelberg, Germany. “This result underscores how x-ray studies of distant quasars provide an essential means of studying the growth of the most distant supermassive black holes.

The light detected by this jet 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 microwave cosmic background radiation (CMB) left over from the Big Bang was much higher than it is today.

As the electrons in the jet fly away from the black hole at a speed close to the speed of light, they move and collide with the photons making up the CMB radiation, increasing the energy of the photons in the x-ray range. to be detected by Chandra. In this scenario, the brightness of the x-rays is greatly increased compared to the radio waves. This agrees with the observation that the large x-ray jet function has no associated radio emission.

“Our results show 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 from JPL. “Or to put it another way, X-ray observations in the future may be the key to unlocking the secrets of our cosmic past.”

An article describing these results has been accepted for publication in The Astrophysical Journal.