James Webb becomes a dark matter tracker with a little trick

James Webb becomes a dark matter tracker with a little trick


Data from the James Webb Telescope has been used to detect regions where dark matter is distributed around galaxies. Competence!

A little trick turned James Webb into a “hunter” of dark matter🇧🇷 By detecting extragalactic light in galaxy clusters, the infrared telescope can reveal the distribution of this invisible matter and provide us with a new view of the universe.

Dark matter is one of the greatest challenges in physics, as it is the only means of interaction with baryonic matter (“normal” matter, which includes anything we can observe in any way).

Scientists are sure dark matter exists because it has mass and therefore interacts gravitationally. In fact, observations of galaxies, gravitational lensing and galaxy clusters can only be explained by adding dark matter to their surroundings.

Extragalactic light and dark matter

Today, astronomers know that this invisible matter underlies the formation and evolution of galaxies. One of the tests (pictured just below) is gravitational lensing, when a very distant galaxy is magnified by the closest galaxy cluster to us. But these lenses are made up of more mass than would be expected excluding dark matter.




James Webb becomes a dark matter tracker with a little trick

Astronomers also detect the presence of dark matter in the X-ray (pink) and baryonic matter (blue) maps of various colliding galaxy clusters (image below). The map shows a clear separation between normal matter and gravitational effects, which is one of the strongest evidence for dark matter.

This doesn’t mean that dark matter appears in the images; what happens is a little more complicated, but elegant. The X-rays, in this case, are revealing where collisions between galaxies create temperatures above several hundred thousand degrees, creating light from outside the galaxies but inside the cluster.



This light is called “intergalactic light, because the source is stars and other phenomena – including collisions of matter when galaxies are about to merge – outside individual galaxies. But not all intergalactic light is the result of these baryonic matter processes only.

As galaxies interact within clusters, stars and tidal streams are removed and sent out of the galaxies to which they belong. While we can’t make out these individual stars, they still shine, emitting a faint intergalactic light.

As dark matter gravitationally attracts these stars, light evolves as a dark matter tracker, as is the case in the Tadpole Galaxy. Its massive tail is evidence of tidal interactions, when a gravitational force pulls and stretches galactic matter, forming a thread that contracts under its own gravity to form stars.

In the case of the Tadpole Galaxy, the tail is about 280,000 light-years long and reveals the stars by following the distribution of dark matter in that region, creating intergalactic light.

Despite being able to detect dark matter with these techniques, telescopes have not yet been able to provide enough detailed data for an even more in-depth study. That may change with the James Webb Telescope.

James Webb detects dark matter

In a new study, published in The letters from the astrophysicist diary by researchers Mireia Montes and Ignacio Trujillo, the James Webb telescope was used with the technique of observing intergalactic light to study dark matter.

The pair used the first deep-field image from JWST and calibrated the data to extract more information about intergalactic light. In the 3-frame animation below, we see the original deep-field image, a color-inverted version, and a contrast/brightness-enhanced version to enhance intergalactic light.

They found a light created by luminous fusions and additions caused by external factors. There are many lights that come from outside the galaxy cluster and are confused with the light inside the cluster, but the duo managed to separate them all and eliminate the brightness of the external objects.

The remaining light suggests that galactic mergers within the clusters are the main source of intergalactic light that forms stars. Because matter that emits this brightness responds to dark matter, the study authors demonstrated that the dark matter tracking technique is excellent if James Webb’s data is used.

This technique already existed with other infrared telescopes, but the James Webb is the most powerful of them. That is: we could have a lot of news about the dark matter of the universe in the near future.

Source: IAC extension🇧🇷 Start with a bang

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