July 17, 2024
1 Solar System Way, Planet Earth, USA

Did Dark Matter Collision Shape the El Gordo Galaxy Cluster?

White and blue stars and gas on black background.  Dark matter.
This Hubble space telescope The image shows the most massive galaxy cluster known to exist so far. It existed when the universe was less than half its current age of 13.8 billion years. The group – El Gordo, Spanish for Fat – contains several hundred galaxies that swarm under a collective gravitational pull. New article suggests interaction with yourself dark matter explains the internal interactions of the cluster. Image via POT/ ESA/J. Jee (University of California, Davis).
  • New study suggests dark matter may have collision properties, defying the standard cosmological model.
  • The study analyzed the behavior of dark matter in the El Gordo cluster, supporting the theory of self-interacting dark matter.
  • Massive galaxy clusters like El Gordo They provide valuable information about the collision properties of dark matter.

Dark matter interacting with itself explains El Gordo

Scientists believe that 27% of the universe is made up of dark matter, a mysterious but invisible substance. Dark matter has never been directly detected. Doesn't seem to interact with regulars. baryon matter (the type of matter we are made of), or even with radiation, except through the force of gravity. But can dark matter interact with itself? If so, it could explain the behavior of the largest known galaxy clusters in the universe, called the El Gordo galaxy cluster.

Ricardo Valdarnini at the Scuola Internazionale Superiore di Studi Avanzati (SISSA) in Trieste, Italy, reported In a recent analysis that dark matter does interact with yourself. Valdarnini observed mass concentrations in the El Gordo galaxy cluster. He found that the distribution supports a model of dark matter interacting with itself (SIDM). He peer reviewed diary Astronomy and Astrophysics published the studio on April 12, 2024.

Fat – Spanish for Fat and cataloged as ACT-CL J0102-4915, it is the largest known merger of galaxy clusters observed so far. Measurements from the Hubble Space Telescope suggest El Gordo, which is 9.7 billion Light years of Earth, contains 3 million trillion (3,000,000,000,000,000) times the mass of our sun. But only part of that is normal stuff. Most of it (about 90%, according to Valdarnini) is invisible dark matter.

Cold dark matter accumulates too much

Valdarnini's work on the mass distribution at El Gordo strongly suggests that fragments of dark matter are colliding with each other. Those interactions helped shape El Gordo's ultimate form. He explained what he found in a SISSA Press release Since May:

The calculations indicated that in this cluster the physical separation observed between the points of maximum density of the dark matter and those of the other components of the mass can be explained using the model called SIDM (self-interactive dark matter), unlike the standard model. one.

The standard explanation: cold dark matter (CDM) – says the material doesn't sit well with others. It only interacts gravitationally with normal matter, but does not appear to come into contact with it or itself. But that's not what we find in El Gordo.

The most significant result of this simulation study is that the relative separations observed between the different mass centroids of the El Gordo cluster are naturally explained if dark matter interacts with itself.

Invisible mass makes El Gordo crooked

El Gordo's mass has three parts: galaxies, gas and dark matter. According to the CDM model, the center of mass of galaxies and dark matter should be the same. In the SIDM model, however, they should be different. And that's what the mathematical models of the El Gordo data show.

A notable feature is the location at the peaks of the different mass components. Unlike what we see in the bullet groupAnother important example of a colliding cluster, the X-ray peak (from El Gordo) precedes the southeastern dark matter peak.

That means, says Valdarnini, that we have probably found dark matter interacting with itself in El Gordo.

For this reason, these findings provide an unambiguous signature of the behavior of dark matter exhibiting collisional properties in a highly energetic, high-energy atmosphere.redshift cluster collision.

However, there is still work to be done, he notes. Their El Gordo simulation numbers do not perfectly match the observations.

This suggests that current SIDM models should be considered only as a low-order approximation. And the underlying physical processes that describe the interaction of dark matter in major cluster mergers are more complex than can be adequately represented by the commonly assumed approach based on the scattering of dark matter particles.

That said, Valdarnini's work provides strong evidence that dark matter interacts with itself. And knowing that could lead to a new understanding of a vast, invisible portion of our universe.

Bottom line: A recently published analysis of the El Gordo galaxy cluster suggests that its internal behavior could be the result of self-interacting dark matter (SIDM).

Read more: Dark matter, a mysterious substance… What is it?

Source: A Hydrodynamic/N-Body Simulation Study of the Merging El Gordo Cluster: A Compelling Case for Self-Interacting Dark Matter?

Via Scuola Internazionale Superiore di Studi Avanzati (SISSA)

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