Heavy axion-like particles and MeV decay photons from nearby type Ia supernovae

Abstract

Abstract Axion-like particles (ALPs) are hypothetical bosons which may couple with photons. Since many ALPs can be emitted from hot and dense astrophysical plasma, nearby supernovae (SNe) are a possible probe into their properties, including the ALP mass ma and the coupling constant gaγ between ALPs and photons. I calculate the ALP emission from a type Ia SN (SN Ia) model with near-Chandrasekhar mass, finding that ALP luminosities from SNe Ia reach ∼1043(gaγ/10−10 GeV−1)2 erg s−1 if ma ≲ 1 MeV. Heavy ALPs emitted from SNe are unstable and decay into photons. I predict the time delay and the flux of decay photons that reach Earth from a nearby SN Ia, finding that the decay photons may provide a constraint on gaγ which is as stringent as the SN 1987A limit if an SN Ia is located 1 kpc away or closer and next-generation MeV γ-ray satellites observe it ∼1–10 yr after the explosion.