# Gamma-ray lines in modern astrophysics

## TL;DR

Gamma-ray line astronomy offers unique insights into cosmic phenomena like chemical enrichment, cosmic ray propagation, and transient events, with recent advances from INTEGRAL shaping our understanding of the universe.

## Contribution

This paper highlights the significant role of gamma-ray spectroscopy, especially from INTEGRAL, in advancing modern astrophysics and discusses future prospects in the field.

## Key findings

- Gamma-ray lines reveal chemical enrichment processes in the universe.
- Positron annihilation lines provide insights into cosmic ray propagation.
- INTEGRAL has significantly contributed to gamma-ray astrophysics understanding.

## Abstract

Gamma-ray astronomy provides a direct window into the most violent, dynamic processes in the Universe. MeV gamma-ray astronomy in particular allows us to directly observe the process of chemical enrichment of the interstellar medium (ISM) through the decay of radioactive isotopes synthesized by stars and compact objects during their lives, in their death throes and after their deaths. Moreover, gamma-ray lines such as the positron annihilation line can give us a unique view into the propagation of cosmic rays in the Galaxy, as well as hints about unusual transient phenomena that may be responsible for producing the positrons. With modern astrophysics moving forward into a new era of multimessenger astrophysics, the important contributions of MeV gamma-ray astronomy must not be overlooked. I briefly outline some of the important contributions gamma-ray spectroscopy with \textit{INTEGRAL} has made to our understanding of the universe, and the future perspectives for this dynamic field of astrophysics.