Saturday , May 15 2021

Dark substance on the move

Creating stars in small dwarf galaxies can slowly "heat" the dark matter, pushing it outward. The left image shows the density of hydrogen gas of simulated dwarf galaxies, viewed from above. The right image shows the same for the actual dwarf galaxy, IC 1613. In the simulation, repeated gas flow and leakage cause fluctuation of the gravitational field strength in the center of the dwarf. The dark matter reacts to that by migration from the center of the galaxy, an effect known as & quot; warming up dark matter & quot ;. Letters: J. Read et al.

Scientists have found evidence that the dark matter may heat up and move, as a result of star formation in galaxies. The findings provide the first observational evidence for the effect known as & quot; warming up dark & ​​quot; and give new indications of what dark matter means. Research is now published in the journal Monthly Reports by the Royal Astronomical Society.

In the new work, scientists from Surrey University, Carnegie Mellon University, and ETH Zurich went on a quest for dark matter evidence at the centers of nearby dwarf galaxies. Dwarf galaxies are small, weak galaxies that are usually found in orbit around larger galaxies like our Milky Way. I can keep traces that will help us better understand the nature of dark matter.

Dark matter is believed to be the majority of the mass of the universe. However, since it does not affect the light in the same way as normal matter, it can only be observed through its gravitational effects. However, the key to studying can be how the stars are formed in these galaxies.

When stars are formed, strong winds can eject gas and dust from the heart of the galaxy. As a result, the center of the galaxy has a smaller mass, which affects how gravity it is felt in the remaining dark matter. With less gravitational attraction, dark matter gets energy and migrates away from the center, what is called 'warming up dark matter' & # 39;

The astrophysic team measured the amount of dark substance in the centers of 16 dwarf galaxies with a very different star creation history. They discovered that the galaxies that had long ago ceased to form stars had larger density of dark matter in their centers than those that still make stars. This confirms the theory that older galaxies had less warming up of dark matter.

Professor Justin Read, lead author of the study and head of the Department of Physics at Surrey University, said: "We've found a remarkable relationship between the amount of dark matter in the centers of those little dwarfs and the amount of stars. It seems to be a dark substance in the centers of dwarfs that create stars" heated "and excited."

The findings give new restriction to dark matter models: dark matter must be able to form dwarf galaxies that show the range of central density, and these densities must relate to the amount of star formation.

Professor Matthew Walker, co-author of Carnegie Mellon University, added: "This study can be a proof of a smoking rifle that takes us closer to understanding what dark matter is, and it helps to motivate the search for dark matter particles."

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

Explore further:
Astronomers discover that dark matter dominates through space time

More information:
J et Read et al, dark matter is heated in dwarf galaxies, Monthly Reports by the Royal Astronomical Society (2018). DOI: 10,1093 / mnras / sty3404

Journal reference:
Monthly Reports by the Royal Astronomical Society

University of Surrey

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