More than 10⁴³ positrons (i.e., anti-matter electrons) annihilate in the Inner Galaxy every second. We know this from the distinctive gamma-ray annihilation line signal we detect from this part of the Milky Way. But where do these positrons come from? Are they a signal of dark matter?

In this project you will use a new cosmic ray propagation code, CRIPTIC, to model the injection, transport, and final annihilation of positrons in the interstellar medium of the inner Galaxy. This modelling is expected to severely constrain different origin scenarios for the annihilating positrons.