Speaker
Description
Magnetars, with their extreme magnetic fields, are ideal laboratories to constrain axion-like particles. Historically, axions are beyond-the-Standard-Model particles introduced to explain the strong CP problem of QCD. Axion-like particles are generalizations of axions that are ubiquitous in top-down approaches to high-energy physics like string theory. If they exist, they are however difficult to constrain due to their light mass and weak coupling.
Since axion-like particles mix with Standard Model photons in the presence of magnetic fields, they can be investigated through axion-to-photon conversion in the magnetosphere, leading to modifications to the observed photon spectra of magnetars. In this talk, we will discuss the conversion probability of axion-like particles created in the core of magnetars to oscillate into photons as they travel through the magnetosphere. For an arbitrary initial state at the magnetar's surface, we will focus on the effects of the conversion, computing the resulting intensities and polarizations of the photon signal originating from axion-like particles. By comparing with observed luminosities for several magnetars, we will put bounds on the axion-like particle parameter space.
