Astronomers who use the Hubble Space Telescope of the NASA / ESA have employed a revolutionary method for detect dark matter in the galaxy clusters.
The method allows astronomers to "see" the distribution of dark matter more accurately than any other method used to date and could possibly be used to explore the ultimate nature of dark matter. The results were published in the Monthly Notices magazine of the Royal Astronomical Society.
In recent decades, astronomers have tried to understand the true nature of the mysterious substance that constitutes most of the matter in the Universe (dark matter) and map its distribution in the Universe. Now, two astronomers from Australia and Spain have used data from the Frontier Fields program of the NASA / ESA Hubble Space Telescope to study precisely the distribution of dark matter.
"We have found a way to 'see' dark matter," explains Mireia Montes, from the University of New South Wales, lead author of the study. "We have found that the very dim light in the clusters of galaxies, the inconsequential light, shows how dark matter is distributed"
Intracumular light is a by-product of the interactions between galaxies. In the course of these interactions, individual stars are stripped of their galaxies and float freely within the cluster. Once free of their galaxies, they end up where the majority of the mass of the cluster resides, mainly dark matter.
"These stars have an identical distribution to dark matter, to the extent that our current technology allows us to study," said Montes. Both dark matter and these isolated stars, which form the intricate light, act as components without collision. These follow the gravitational potential of the cluster itself. The study showed that Intracumular light is aligned with dark matter, tracing its distribution with greater precision than any other method that is based on the light markers used so far.
This method is also more efficient than the more complex method of using gravitational lens. While the latter requires both an accurate reconstruction of the lens and time-consuming spectroscopic campaigns, the method presented by Montes only uses deep images. This means that more groups can be studied with the new method in the same amount of observation time.
The results of the study introduce the possibility of exploring the ultimate nature of dark matter. "If the dark matter is self-interactive, we could detect this as small deviations in the distribution of dark matter compared to this very weak stellar radiance ", points out Ignacio Trujillo, of the Institute of Astrophysics of the Canary Islands, co-author of the study.
Currently, all that is known about dark matter is that it seems to interact with the regular matter gravitationally, but not otherwise. Discovering that self-interaction would place significant restrictions on their identity.
For now, Montes and Trujillo plan to study more than the original six groups to see if their method is still accurate. Another important test of your method will be the observation and analysis of additional galaxy groups by other research teams, to add to the data set and confirm their findings.
The team can also expect the application of the same techniques using future space telescopes such as the James Webb Space Telescope, which will have even more sensitive instruments able to resolve the weak intracluster light in the distant Universe.
"There are interesting possibilities that we should be able to explore in the next few years studying hundreds of galaxy clusters," concludes Ignacio Trujillo.