Brightening the Universe: New Directions for Astrophysical Axion Searches

The nature of dark matter and what lies beyond the Standard Model (SM) of particle physics are among the most profound unanswered questions in fundamental physics.

We propose a pioneering approach to detect axions, prime candidates for dark matter and well-motivated extensions of the SM, through novel theoretical models and unexplored astrophysical systems. Our proposal has three key ingredients: 1) Theory.

We will develop a conceptually new theory where axion dark matter emerges as a relativistic gas trapped in “relic pockets” of the false vacuum state following a cosmic phase transition.

Our theory is simple, predictive, and draws on natural ingredients from theoretical cosmology and high-energy physics, yet the resulting predictions contrast existing dark matter paradigms. 2) Phenomenology.

We will spearhead the use of cosmic magnetohydrodynamic simulations and investigate plasma instabilities to identify new axion observables from the most promising astrophysical systems, including galaxy clusters. 3) Observations.

We will leverage existing and upcoming astronomical observations from X-ray and gamma-ray observatories to conduct the first searches for dark matter relic pockets and, model-independently, search for astrophysical axions from galaxy clusters.

Our work will probe deep into the axion parameter space and potentially lead to transformative discoveries in understanding the universe´s dark components.