Electromagnetic Bursts from Mergers of Oscillons in Axion-like Fields
  We investigate the bursts of electromagnetic and scalar radiation resulting
from the collision, and merger of oscillons made from axion-like particles
using 3+1 dimensional lattice simulations of the coupled axion-gauge field
system. The radiation into photons is suppressed before the merger. However, it
becomes the dominant source of energy loss after the merger if a resonance
condition is satisfied. Conversely, the radiation in scalar waves is dominant
during initial merger phase but suppressed after the merger. The backreaction
of scalar and electromagnetic radiation is included in our simulations. We
evolve the system long enough to see that the resonant photon production
extracts a significant fraction of the initial axion energy, and again falls
out of the resonance condition. We provide a parametric understanding of the
time, and energy scales involved in the process and discuss observational
prospects of detecting the electromagnetic signal.
