2024-01-03 17:57:17
Dark matter minihalos spread across the Cosmos could function as highly sensitive probes of primordial magnetic fields. – LUCIE CHRASTECKA
MADRID, 3 Ene. (EUROPA PRESS) –
Dark matter minihalos scattered across the cosmos could function as highly sensitive probes of primordial magnetic fields, originated at the dawn of the Universe.
This is what emerges from a theoretical study carried out by SISSA (International School of Advanced Studies) and published in Physical Review Letters.
Present on immense scales, magnetic fields are found everywhere in the universe. However, its origin remains a topic of debate among scholars. An intriguing possibility is that magnetic fields they originated near the birth of the universe itself; that is, they are primordial magnetic fields.
The new study shows that if the magnetic fields are truly primordial, they could lead to increased perturbations in the density of small-scale dark matter. The final effect of this process would be the formation of dark matter minihalos which, if detected, would suggest a primordial nature of the magnetic fields. Thus, in an apparent paradox, the invisible part of our universe could be useful to resolve the nature of a component of the visible one.
“Magnetic fields are omnipresent in the cosmos,” explains it’s a statement Pranjal Ralegankar, SISSA researcher and author of the research. “A possible theory about their formation suggests that those observed so far could occur in the early stages of our universe.”
“However, this proposition lacks an explanation in the standard model of physics. To shed light on this aspect and find a way to detect ‘primordial’ magnetic fields, with this work we propose a method that we could define as ‘indirect’. Our approach is based on one question: What is the influence of magnetic fields on dark matter?” It is known that there is no direct interaction. Still, as Ralegankar explains, “there is an indirect one that occurs through gravity.”
Primordial magnetic fields can enhance electron and proton density perturbations in the primordial universe. When these become too large, they influence the magnetic fields themselves. The consequence is the suppression of small-scale fluctuations.
Ralegankar explains: “In the study, we showed something unexpected. The growth of baryon density gravitationally induces the growth of dark matter perturbations without possibility of subsequent cancellation. This would result in its collapse on a small scale, producing dark matter mini-halos “. The consequence, continues the author, is that even if the fluctuations in the density of the baryonic matter are cancelled, they would leave traces through the minihalos, all of this solely through gravitational interactions.
“These theoretical findings,” concludes Pranjal Ralegankar, “also suggest that the abundance of minihalos is not determined by the current presence of primordial magnetic fields, but rather by their strength in the primordial universe. Therefore, a detection of minihalos Dark matter halos would reinforce the hypothesis that magnetic fields formed very early, even a second after the Big Bang“.
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