University of Surrey | 2018 Apr 06
Astrophysicists from the University of Surrey and the University of Edinburgh have created a new method to measure the amount of dark matter at the centre of tiny “dwarf” galaxies.
Dark matter makes up most of the mass of the Universe, yet it remains elusive. Depending on its properties, it can be densely concentrated at the centres of galaxies, or more smoothly distributed over larger scales. By comparing the distribution of dark matter in galaxies with detailed models, researchers can test or rule out different dark matter candidates.Click to play embedded YouTube video.
The tightest constraints on dark matter come from the very smallest galaxies in the Universe, “dwarf galaxies”. The smallest of these contain just a few thousand or tens of thousands of stars – so-called “ultra-faint” dwarfs. Such tiny galaxies, found orbiting close to the Milky Way, are made up almost entirely of dark matter. If the distribution of dark matter in these tiny galaxies could be mapped out it could provide new and exciting information about its nature. However, being entirely devoid of gas and containing very few stars, until recently there was no viable method for making this measurement.
In a study published by the Monthly Notices of the Royal Astronomical Society (MNRAS), a team of scientists from the University of Surrey have developed a new method to calculate the inner dark matter density of dwarf galaxies, even if they have no gas and very few stars. The key to the method is to make use of one or more dense star clusters orbiting close to the centre of the dwarf. ...
Probing Dark Matter with Star Clusters: A Dark Matter Core in the Ultra-Faint Dwarf Eridanus II - Filippo Contenta et al
- Monthly Notices of the RAS 476(3):3124 (May 2018) DOI: 10.1093/mnras/sty424
arXiv.org > astro-ph > arXiv:1705.01820 > 04 May 2017 (v1), 04 Apr 2018 (v3)