# Evidence of a spectral break in the gamma-ray emission of the disk component of Large Magellanic Cloud: a hadronic origin?

## TL;DR

This paper reports evidence of a spectral break around 500 MeV in the gamma-ray emission of the Large Magellanic Cloud's disk, supporting a hadronic origin via pion decay, based on Fermi-LAT observations.

## Contribution

The study provides observational evidence of a spectral break consistent with pion-decay in the gamma-ray spectrum of the LMC, supporting hadronic cosmic ray interactions as the emission source.

## Key findings

- Spectral break observed at ~500 MeV in LMC gamma-ray emission.
- Data analysis extends down to 60 MeV using Fermi-LAT.
- Results support pion-decay as the dominant emission mechanism.

## Abstract

It has been suggested that high-energy gamma-ray emission ($>100{\rm MeV}$) of nearby star-forming galaxies may be produced predominantly by cosmic rays colliding with the interstellar medium through neutral pion decay. The pion-decay mechanism predicts a unique spectral signature in the gamma-ray spectrum, characterized by a fast rising spectrum and a spectral break below a few hundreds of MeV. We here report the evidence of a spectral break around 500 MeV in the disk emission of Large Magellanic Cloud (LMC), which is found in the analysis of the gamma-ray data extending down to 60 MeV observed by {\it Fermi}-Large Area Telescope. The break is well consistent with the pion-decay model for the gamma-ray emission, although leptonic models, such as the electron bremsstrahlung emission, cannot be ruled out completely.