dark matter tagged posts

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...

The gamma-ray excess (shown in yellow-white) at the heart of M31 hints at unexpected goings-on in the galaxy’s central region. Scientists think the signal could be produced by a variety of processes, including a population of pulsars or even dark matter. Credit: NASA/DOE/Fermi LAT Collaboration and Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF

NASA’s Fermi Gamma-ray Space Telescope has found a signal at the center of the neighboring Andromeda galaxy that could indicate the presence of dark matter. The gamma-ray signal is similar to one seen by Fermi at the center of our own Milky Way galaxy. Gamma rays are the highest-energy form of light, produced by the universe’s most energetic phenomena...

Kinematic Clues to Bar Evolution for Galaxies in the Local Universe: Why the Fastest Rotating Bars are Rotating Most Slowly. The Astrophysical Journal, 2017; 835 (2): 279 DOI: 10.3847/1538-4357/835/2/279

Fastest spinning bars are rotating most slowly because of dark matter. Why do the majority of astronomers believe in dark matter: matter whose composition is unknown but which seems to make up 80% of the mass of the galaxies? The concept was invented in the 1930’s by Fritz Zwicky who used it to explain why the galaxies in the Coma cluster are moving much more quickly than can be explained in terms of their known masses...