Dark matter is one of the biggest mysteries of physics today. Based on observations received from cosmologists, we know that all matter that appears around us – each proton, electron, and neutron – comprises just a small fraction of all matter present in the universe. So what is all this other matter? Physicists theorize that it must be a type of particle that we cannot currently see directly, although we can see its effects. They call this imaginary particle dark matter.
The study of very large galaxies is helpful in understanding dark matter because we know the dark matter cluster around galaxies to form a halo. When the gravitational effect of these galaxies is more pronounced, the galaxy in question is larger. So recently, the Hubble Space Telescope captured this image of the giant galaxy cluster Abell 3827, which creates a strong gravitational lensing effect.
This galaxy cluster was the site of a debate on the nature of dark matter. In 2015, some scientists believed they saw dark matter interacting with other dark matter in the region when they saw a cloud of dark matter that was moving around the galaxy. This means that there will be a type of Dark Matter particle that differs from the standard approach of Dark Matter, called the Lambda Cold Dark Matter model.
However, the idea was eventually rejected when the same group of scientists made more observations in 2017, using the MUSE instrument of Very Large Telescope to improve their model of the Atacama Large Millimeter / Submillimeter Array as well as the cluster. Data added.
This new set of observations “reveals an unusual configuration of strong gravitational lensing in a cluster core with at least seven lensed images of a single background spiral galaxy,” the scientists wrote. “New spectroscopic data enable better subtraction of foreground light, and better detection of multiple background images. The approximate distribution of dark matter is consistent with the focus on galaxies, as expected. [the Lambda cold dark matter model]”
This means that the new data showed dark matter behaving as expected in traditional approaches, and did not support the idea of self-interacting dark matter. Scientists continue to study dark matter using instruments such as the upcoming European Space Agency Euclid Telescope to try to understand more about this mysterious phenomenon.