Electromagnetic Bursts from Mergers of Oscillons in Axion-like Fields

TL;DR

This study uses 3+1D lattice simulations to analyze electromagnetic and scalar radiation from axion-like oscillon mergers, revealing resonance-driven photon emission as a key energy loss mechanism with potential observational signatures.

Contribution

It provides the first detailed simulation-based analysis of electromagnetic bursts from oscillon mergers in axion-like fields, including backreaction effects and resonance conditions.

Findings

Photon radiation dominates energy loss after merger under resonance.

Scalar radiation is dominant during initial merger phase.

Resonant photon production can significantly deplete axion energy.

Abstract

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.