About 23% of the universe is made up of dark matter and despite how abundant it is, with current instruments we have not been able to detect it directly. Thanks to the gravitational influence it exerts on stars and galaxies, we know it’s there. Now, by measuring the mass of a nearby dwarf galaxy called the Triangle II Galaxy, astronomer from the California Institute of Technology (USA) Evan Kirby appears to have discovered the highest concentration of dark matter in a known galaxy. .
The Triangle II Galaxy is a small, nondescript dwarf galaxy close to the Milky Way that has only 1,000 stars but is unusually massive for a galaxy of this size. To deepen this fact, Kirby measured the speed of six stars (the only ones that are bright enough to be detected by the Keck Observatory in Hawaii), discovering that their mass was much greater than that of the around a thousand stars with the what this dwarf galaxy tells.
“The total mass that I measured was much, much greater than the mass of the total number of stars, which implies that there is a ton of densely populated dark matter that contributes to the total mass. The ratio of dark matter to light matter is the highest of any galaxy that we know of. After I had done my measurements, I was just thinking … wow! Kirby says.
This small galactic neighbor has thus become an excellent candidate for finally direct detection of the elusive dark matter. Detecting its gamma radiation in the middle of the galactic noise produced by other sources such as a pulsar, is not an easy task. The advantage in this case is that the Triangle II Galaxy is fairly quiet; It does not have gas reserves or materials for the formation of new stars, so the slightest gamma ray signal would not only be easy to detect but also difficult to mistake for something else in this galaxy that astronomers consider “dead.”
The study has been published in the Astrophysical Journal Letters.
