Moving through cosmic forests and spider webs in deep space in search of answers on the origin of the Cosmos. “We have tested a scenario in which dark matter is composed by non-stellar black holes, formed in the primordial Universe” says Riccardo Murgia, lead author of the study recently published in Physical Review Letters. The research was carried out together with his colleagues Giulio Scelfo and Matteo Viel of SISSA – International School for Advanced Studies and INFN – Istituto Nazionale di Fisica Nucleare (Trieste section) and Alvise Raccanelli of CERN.
In this work, the scientists have concentrated on the abundance of PBHs that are 50 times larger than the solar mass. In short, the researchers have tried to better describe several parameters linked to their presence (specifically mass and abundance) by analysing the interaction of the light emitted from extremely distant quasars with the cosmic web, a network of filaments composed of gas and dark matter present throughout the Universe. Within this dense weave, the scholars have concentrated on the “Lyman-alpha forest”, namely the interactions of the photons with the hydrogen of cosmic filaments, which presents characteristics closely linked to the fundamental nature of dark matter.
The results of the study seem to disadvantage the case that all dark matter is composed of a certain type of primordial black holes (those with a mass greater than 50 times that of the sun) but they do not totally exclude that they could constitute a fraction of it. These conclusions, important for the construction of new theoretical models and for the development of new hypotheses about the nature of dark matter, offer much more precise indications for tracing the intricate path to understanding one of the largest mysteries of the Cosmos.