The Triangulum II is a dead galaxy because it lacks necessary gas and material to create new stars. The remaining stars in this galaxy are only about 1,000 stars and only six stars were luminous enough to be detected by the Keck telescope of the Caltech astronomers.
The observation of dark matters in galaxies like Triangulum II basically starts by looking at the spin of galaxies and the interactions of stars inside galactic clusters. In such faint concentration of stars found in Triangulum II, the detection of dark matters could only be possible through the "smoking gun" of WIMPs annihilation, according to Caltech.
The WIMPs or Weakly Interacting Massive Particles are dense cloud found in the Triangulum II. One unique characteristic of the WIMPs is that these particles annihilate with one another during collision and emit gamma ray, according to The Star.
In theory, the annihilation of WIMPs indicates that the presence of gamma-ray radiation emitted from the Triangulum II will be readily observable because the waves will be detected on Earth.
Another study shows that the stars outside of Triangulum II galaxy are moving faster and thus, ripping Triangulum II apart with their strong gravitational field. The Caltech team, which discovered the capability of Triangulum II for dark matters research, said that their next steps are to make measurements to confirm if these outer stars are actually moving faster than the inner ones.
If the contrary is true, the stars will create, "dynamic equilibrium", which would make the Triangulum II an excellent candidate for detecting dark matter with gamma rays. This marks the start of grasping the powerful effects of dark matter, which remains unfathomable at present.