Precise measurement of pion-bump structure using future MeV gamma-ray detectors

TL;DR

This paper explores how future MeV gamma-ray detectors can precisely identify the pion-bump spectral feature, providing crucial evidence for hadronic cosmic ray acceleration in supernova remnants by overcoming current instrument limitations.

Contribution

It analyzes the potential of upcoming gamma-ray missions to detect the pion-bump feature, enhancing understanding of cosmic ray origins and particle acceleration mechanisms.

Findings

Future MeV gamma-ray detectors can improve pion-bump detection.

Detection potential varies with instrument resolution and energy coverage.

Study highlights importance of gamma-ray spectral analysis in astrophysics.

Abstract

The pion-bump structure in the gamma-ray spectrum is a direct proof for the hadronic origin of the gamma rays, and thus the decisive evidence for the acceleration of hadronic cosmic rays in astrophysical objects. However, the identification of such a spectral feature is limited by the resolution and energy coverage of current gamma-ray instruments. Furthermore, there are unavoidable bremsstrahlung emissions from secondary and primary electrons, which may dominate the gamma-ray emission below the pion-bump. Thus, the study of this gamma-ray emission component can provide unique information on the acceleration and confinement of high-energy particles. In this paper, we studied the predicted gamma-ray spectrum assuming both hadronic or leptonic origin in mid-aged supernova remnants W44, we discuss the detection potential of future MeV missions on these emissions and possible implications.