A leading hypothesis on the nature of Dark Matter is that it is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced moments after the Big Bang. If WIMPs are the dark matter, then their presence in our galaxy may be detectable via scattering from atomic nuclei in detectors as shown in this cartoon:
Gamma-ray bursts (GRBs) are short flashes of photons thought to originate from collapsing stars. These strong pulses have energies in the X-ray to gamma-ray ranges and time scales ranging from a few milliseconds to around 100 seconds. The separation between "short" and "long" bursts is around two seconds.
We cannot see one of the universe’s primary constituents: dark matter. The reason is simple: it's dark. But we can infer where it is located from observations of distant galaxies because of a key property of light, namely that it does not always travel in straight lines.