Tuesday , August 3 2021

Dark matter in motion



The formation of stars in small dwarf galaxies can slowly "warm" the dark matter, pushing it outward. The left picture shows the density of the hydrogen gas of the simulated dwarf galaxy, viewed from above. The right picture shows the same about the real dwarf galaxy, IC 1613. In the simulation, the repeated inflow and outflow of gas causes the gravitational field to be changed in the center of the dwarf. The dark matter reacts to this by migrating out of the center of the galaxy, an effect known as 'dark matter darkness'. Credit: J. Read et al.

Scientists have found evidence that dark matter can warm up and move as a result of the formation of stars in galaxies. Findings give the first observation evidence of an effect known as "heating dark matter" and give new clues as to what makes the dark matter. The survey was published today in the journal Monthly notifications of the Royal Astronomical Society.


In the new work, scientists at the University of Surrey, Carnegie Mellon University and ETH Zurich began to catch evidence of dark matter in the centers of nearby galaxies in the dwarf spheres. Dwarf galaxies are small, weak galaxies that are usually located around orbiting larger galaxies like our Milky Way. They can have clues that can help us better understand the nature of the dark matter.

Dark matter is thought to constitute the bulk of the mass of the universe. However, since it does not connect to light in the same way as the normal matter, it can be noted only through its gravitational effects. However, the key to studying this can lie in how the stars form in these galaxies.

When the stars form, strong winds can push gas and dust from the heart of the galaxy. As a result, the center of the galaxy has less mass, which affects the gravity that is felt by the remaining dark matter. With a less gravitational attraction, the dark matter gets energy and migrates from the center, an effect called "heating of dark matter".

The team of astrophysicists measures the amount of dark matter in the centers of 16 dwarf galaxies with many different star formation stars. They discovered that galaxies that have ceased to form stars have long had higher density of dark matter in their centers than those that still form stars today. This supports the theory that older galaxies had less heating than dark matter.

Professor Justin Read, the lead author of the study and head of the Department of Physics at the University of Surrey, said: "We found a really remarkable relationship between the amount of dark matter in the centers of these small dwarfs and the amount of star formation that they experienced during their lifetime The dark matter in the dwarf star centers seems to be "warmed up" and pushed.

Findings provide a new limitation of dark matter patterns: the dark matter must be able to form dwarf galaxies that exhibit a large number of central densities, and these densities should be related to the amount of star.

Professor Matthew Walker, co-author of the Carnegie Mellon University, added: "This study can be evidence of" smoking with a gun "that leads us to a step closer to understanding what is dark matter. Our conclusion is that it can warm up and move helps to motivate searches for a dark matter particle. "

The team hopes to expand this work by measuring the central density of dark matter in a larger sample of dwarfs, pushing toward even weaker galaxies, and testing a wider range of dark matter models.


Explore further:
Astronomers believe that dark matter dominates the cosmic time

More information:
J I Read et al, Dark matter is heated in dwarf galaxies, Monthly notifications of the Royal Astronomical Society (2018). DOI: 10.1093 / mnras / sty3404

Reference in the newspaper:
Monthly notifications of the Royal Astronomical Society

Provided by:
University of Surrey


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