(Mirror Daily, United States) – Nearby galaxy contains massive dark matter according to a team of Caltech astronomers. The discovery represents the highest amount of dark matter ever to be discovered in a nearby dwarf galaxy. The galaxy is called Triangulum II and it only contains roughly a thousand stars, making it significantly smaller than the Milky Way. It’s what scientists call a dead galaxy, as it has stopped producing new stars a long time ago and the stars that still are there are expected to die soon enough.
However, just because it is small and hasn’t produced stars in a long time doesn’t mean that it is not worth exploring. Caltech astronomers proved that when they discovered a huge mass of dark matter within the dwarf galaxy. It actually seems that the galaxy might contain the highest dark matter to normal matter ratio that has ever been discovered so far. Actually identifying the dark matter would be an important milestone in astrophysics and Triangulum II might be the right place to do that.
The dwarf galaxy seems to be overwhelmed by dark matter. In order to determine just how much dark matter it contains, scientists need to calculate the difference between what the actual mass of the galaxy should be and the mass that the matter which can be seen should have. This difference between what the galaxy’s mass should be and what the mass of the seen objects is would represent the mass of the dark matter in the respective galaxy.
In theory that sounds simple but doing it practically was a bit more complicated. The Caltech astronomers had to use the Low Resolution Imaging Spectrometer at the Keck Observatory in Hawaii. In doing so, they were able to calculate the galactic mass compared to the visible matter mass and came up with a mass-to-light ratio of 3500. Considering that the same ratio for the Univers is only 100, this calculation would indicate that the Triangulum II contains a massive amount of dark matter.
But scientists are worried that the galaxy might not be in dynamic equilibrium, which would mean that the mass-to-light ratio may in fact be influenced by an external force and prove to be inaccurate. Scientists cannot be sure if the ratio is correct because the galaxy has a low luminosity and very few stars that can be measured precisely.
A second research team in France is now measuring the velocities of stars around the galaxy in order to conclude whether they are moving faster than the stars inside the galaxy, as it seems at first glance. If it turns out that the outer stars are not moving faster than the inner ones it will indicate that the galaxy is in dynamic equilibrium and that it can be a great candidate for studying dark matter.
Image source: https://pixabay.com
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