Seminar

Las mañanas IFCA con José Luis Bernal: "Looking for multi-electronvolt axion-like particle dark matter on the sky"

​"Axions and axion-like particles (ALPs) are a natural dark-matter candidate that involves a self-interaction that modifies small-scale clustering, as well as a coupling with photons that causes photon-axion oscillations in the presence of magnetic fields and triggers axion decay into photons. With a viable mass range spanning more than 40 orders of magnitude, the phenomenology of this dark matter model is extremely rich. However, the multi-electronvolt range is very hard to probe. Recently, this range of ALP masses has become very relevant, because their decay may contribute to the 4 sigma excess measured in the cosmic optical background. Therefore, finding new and more sensitive avenues to probe ALPs in this mass range is of utmost importance. In this talk I will review this measurement and the significance of the excess, and discuss two novel probes of the axion-photon coupling for multi-electronvolt ALPs. First, I will report very recent constraints from the attenuation of the flux of gamma-rays from distant blazers, which improve current sensitivities by up to more than one order of magnitude. Afterwards, I will discuss the promising prospects of detecting directly the products of ALP decays with line-intensity mapping surveys, using the strategies I developed to extract the signal from the line-intensity maps."