dark matter tagged posts

Conventional WIMP theories predict that dark matter particles rarely interact with one another, and only weakly with normal matter. Hitoshi Murayama of UC Berkeley and Yonit Hochberg of Hebrew University predict that dark matter SIMPs, comprised of a quark and an antiquark, would collide and interact strongly with one another, producing noticeable effects when the dark matter in galaxies collide. Credit: Kavli IPMU graphic

Colliding galaxies may be evidence in support of new candidate for universe’s elusive dark matter. The nature of dark matter remains elusive, with numerous experimental searches for WIMPs coming up empty-handed and MACHOs all but abandoned...

This is Michal Rawlik of ETH Zürich and Nicholas Ayres of Sussex University. Credit: University of Sussex

Scientists at the University of Sussex have disproved the existence of a specific type of axion – an important candidate ‘dark matter’ particle – across a wide range of its possible masses. The data were collected by an international consortium, the Neutron Electric Dipole Moment (nEDM) Collaboration, whose experiment is based at the Paul Scherrer Institut in Switzerland. Data were taken there and, earlier, at the Institut Laue-Langevin in Grenoble. Professor Philip Harris said: “Experts largely agree that a major portion of the mass in the universe consists of ‘dark matter’. Its nature, however, remains completely obscure...

Abell S1063, a galaxy cluster, was observed by the NASA/ESA Hubble Space Telescope as part of the Frontier Fields programme. The huge mass of the cluster acts as a cosmic magnifying glass and enlarges even more distant galaxies, so they become bright enough for Hubble to see. Credit: NASA, ESA, and J. Lotz (STScI)

Observations may hint at nature of dark matter. Using Hubble, astronomers have discovered that the brightest galaxies within galaxy clusters “wobble” relative to the cluster’s centre of mass. This unexpected result is inconsistent with predictions made by the current standard model of dark matter. With further analysis it may provide insights into the nature of dark matter, perhaps even indicating that new physics is at work.

Invisible halos of elusive dark matter enclose galaxie...

Schematic representation of rotating disc galaxies in the early Universe (right) and the present day (left). Observations with ESO’s Very Large Telescope suggest that such massive star-forming disc galaxies in the early Universe were less influenced by dark matter (shown in red), as it was less concentrated. As a result the outer parts of distant galaxies rotate more slowly than comparable regions of galaxies in the local Universe. Credit: ESO/L. Calçada

Observations of distant galaxies suggest they were dominated by normal matter. The presence of dark matter can explain why the outer parts of nearby spiral galaxies rotate more quickly than would be expected if only the normal matter that we can see directly were present...