Center for Theoretical Physics of the Universe (CTPU)

Novel Astronomical Probes of Axions -- with baselines of Gpc, Mpc, and kpc

by Chen Sun (Tel Aviv U.)

zoom meeting

zoom meeting


Axion couplings to photons can induce photon-axion conversion in the presence of magnetic fields in the Universe. In the first half of talk, I will show that this conversion impacts various cosmic distance measurements, such as luminosity distances to type Ia supernovae (~Gpc away) and angular distances to galaxy clusters (~Mpc size). I will consider different combinations of the most up-to-date distance measurements to constrain the axion-photon coupling. In the second half, I will briefly discuss the axion stimulated decay, a novel approach to constrain axion-photon coupling by observing the echo signals in directions *opposite* to glactic supernova remnants (~kpc away) in the radio band. I will demonstrate that the strength of the "echo" signal from axion stimulated decay depends on the history of photon source. Even though some supernova remnants are dim today, they can lead to the strongest bound of photon-axion coupling for axions around 10^{-6} eV.