ESA Hubble Science Release | 2017 Oct 26
Observations may hint at nature of dark matter
[img3="Abell S1063, the Final Frontier - Credit: NASA, ESA, and J. Lotz (STScI)"]https://cdn.spacetelescope.org/archives ... c1615a.jpg[/img3][hr][/hr]Using the NASA/ESA Hubble Space Telescope, 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.
Dark matter constitutes just over 25 percent of all matter in the Universe but cannot be directly observed, making it one of the biggest mysteries in modern astronomy. Invisible halos of elusive dark matter enclose galaxies and galaxy clusters alike. The latter are massive groupings of up to a thousand galaxies immersed in hot intergalactic gas. Such clusters have very dense cores, each containing a massive galaxy called the “brightest cluster galaxy” (BCG).
The standard model of dark matter (cold dark matter model) predicts that once a galaxy cluster has returned to a “relaxed” state after experiencing the turbulence of a merging event, the BCG does not move from the cluster’s centre. It is held in place by the enormous gravitational influence of dark matter.
But now, a team of Swiss, French, and British astronomers have analysed ten galaxy clusters observed with the NASA/ESA Hubble Space Telescope, and found that their BCGs are not fixed at the centre as expected ...
A Detection of Wobbling Brightest Cluster Galaxies within Massive Galaxy Clusters - David Harvey et al
- Monthly Notices of the RAS 472(2):1972 (Dec 2017) DOI: 10.1093/mnras/stx2084
arXiv.org > astro-ph > arXiv:1703.07365 > 21 Mar 2017 (v1), 09 Aug 2017 (v2)
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