Monday 30 June 2025
Dark matter, a mysterious substance that makes up approximately 27% of our universe, has long been the subject of scientific inquiry. Scientists have sought to understand its properties and behavior, as it plays a crucial role in shaping the cosmos. Recently, researchers from King’s College London, Universidad Autónoma de Madrid, and Stanford University published a paper investigating two types of dark matter candidates: sub-GeV particles and primordial black holes.
The study focused on the X-ray sky, analyzing data from the eROSITA telescope to set new limits on these dark matter scenarios. The researchers used simulations to model how these dark matters would interact with the interstellar medium, generating a diffuse emission in the X-ray range.
Sub-GeV particles are hypothetical particles that could make up dark matter. They would annihilate or decay into electrons and positrons, which would then emit X-rays as they interact with surrounding gas. The researchers found that eROSITA’s data provides stronger constraints on these particles than previous X-ray observations. Specifically, they excluded thermally averaged annihilation cross sections in the range of 10^-27 to 10^-25 cm^3/s and decay lifetimes between 10^24 and 10^25 seconds for particles with masses between 1 MeV and 1 GeV.
Primordial black holes, on the other hand, are hypothetical objects that could have formed in the early universe. They would evaporate through Hawking radiation, releasing low-energy electrons and positrons into space. The researchers found that eROSITA’s data provides new bounds on the dark matter fraction of these objects. Specifically, they set limits on the mass range between 10^15 and 10^17 grams.
The study also revisited previous XMM-Newton constraints, finding that they were approximately four orders of magnitude too stringent due to an incorrect calculation of the instrument’s solid angle. The revised XMM-Newton limits are slightly weaker than those from eROSITA.
These results have significant implications for our understanding of dark matter and its role in shaping the universe. They also highlight the importance of ongoing and future observations, such as those planned by the Square Kilometre Array (SKA), in uncovering the secrets of this mysterious substance.
The researchers’ work demonstrates the power of combining cutting-edge simulations with sensitive astronomical observations to better understand the nature of dark matter. As our understanding of the universe continues to evolve, so too will our ability to probe its most fundamental mysteries.
Cite this article: “New Constraints on Dark Matter Candidates from eROSITA X-ray Observations”, The Science Archive, 2025.
Dark Matter, X-Ray Sky, Erosita, Sub-Gev Particles, Primordial Black Holes, Annihilation Cross Sections, Decay Lifetimes, Hawking Radiation, Square Kilometre Array, Cosmology
