Astronomers have identified the mysterious “engine” of a super-powerful intergalactic light source

(ORDO NEWS) — Bright infrared light emanating from two galaxies in the process of merging has just been pulled out of hiding.

Using JWST, astronomers pinpointed the location of a light source behind a thick wall of the galaxy. dust obscuring it at other wavelengths.

What this light emits is still unknown, but determining where it is will help figure out what it is and why it shines so much brighter than expected.

“The James Webb Space Telescope has brought us completely new views of the universe with its highest spatial resolution and infrared sensitivity,” says astrophysicist Hanae Inami.

“We wanted to find the ‘engine’ that powers this merging galactic system.

We knew this source was deeply hidden by cosmic dust, so we couldn’t use visible or ultraviolet light to find it. now we see that this source dwarfs everything else in these merging galaxies.”

Although the universe is mostly empty space, mergers between galaxies are not uncommon. Massive galaxies are attracted to each other by an inexorable attraction, combining to form larger galaxies.

It’s not even something distant that happens to other galaxies elsewhere: the Milky Way itself is a Frankenstein cosmic monster, partly made up of all the other galaxies it has absorbed over the billions of years of its life.

Throughout the universe, many examples of merging galaxies at different stages have been found, but this is a slow process that can take a long time. from millions to billions of years.

Scientists have to take the examples we have and reconstruct the timeline around them like a single frame from a movie, and the only other examples are single frames from similar but different films.

It’s painstaking work, but it’s one of the best tools for understanding galaxy mergers.

From the light emitted by these mergers, we also know that they are quite alive. While galaxies are mostly cosmic, stars can collide with each other or interact gravitationally, disrupting each other’s orbits.

Clouds of star-forming gas between stars can also collide with each other, creating impacts that can cause violent waves of star formation known as starbursts, visible as infrared light twinkling from dust clouds.

This is what scientists expected to see when they pointed the Spitzer infrared space telescope at a galaxy merger 500 million light-years away, named IIZw096 in 2010.

Instead, they found a bright infrared light shining in the middle of an ongoing collision. Unfortunately, Spitzer didn’t offer a high enough resolution to pinpoint the exact location of the light source, and the mystery had to be put aside.

This is because the longer wavelengths of infrared light do not scatter. dust, as shorter wavelengths do, and Spitzer was the leader at the time, so no other telescope had any hope of getting close. Then JWST appeared and Inami and her colleagues moved closer.

They found that the source is about 70 percent of the mid-infrared light emitted by merging galaxies. Also, while the two galaxies together span about 65,000 light years, the maximum radius of an infrared source is 570 light years. This suggests that the radiation source is very compact.

We know that the material around an active black hole emits a lot of light and that supermassive black holes at the centers of galaxies can merge when they meet at the merging center.

But the arrangement of the light is peculiar; it is not in the center of any of the galaxies where you would normally expect to find such a black hole.

“We want to know what is feeding this source: is it star formation or a massive black hole?” Inami says.

“We will use infrared spectra taken with the James Webb Space Telescope to investigate this. It’s also unusual that the “engine” is located outside the main parts of the merging galaxies, so we’ll find out how this powerful source ended up there.”

The researchers also identified 12 small mid-infrared light sources in the JWST data clustered around a bright “engine”. Some of these smaller clumps have been seen before in the near-infrared data from Hubble, but five of them were new.

They are less mysterious – the light profile corresponds to the activity of star formation – but they indicate that something energetic is happening at the point where two galaxies meet.

The researchers hope that further analysis will lead to the identification of the source of the mysteriously bright light. In the meantime, they are planning more observations to help characterize the dust and gas in and around the ongoing unusual collision.

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