Speaker
Description
Cosmic rays (CRs) are among the non-thermal components of the interstellar medium (ISM) that are ubiquitous throughout the Galaxy. While CR number density can be inferred from local measurements on the Earth, their 3D distribution has largely been explored through simulations. A data-driven 3D map of CRs is essential to better understand the spatial distribution of CRs and to probe the distribution of their sources.
Considering emission related to interactions of CRs with other components of the ISM as tracers of the CR distribution, we focus on the inelastic hadronic collision of CRs with protons in the ISM, which produces gamma rays. We use gamma-ray data from the Fermi Large Area Telescope (LAT) together with a 3D dust map to infer the spatial distribution of cosmic ray protons (CRp) in a morphological matching approach. We infer the CRp density using numerical methods based on information field theory.
We provide our 3D CRp density map as a set of samples that account for statistical uncertainties. Our map shows a smooth but inhomogeneous distribution of CRps and extends in heliocentric distance from 70 pc to 1.25 kpc.
In this talk, I will explain how we build our prior model of the CRp density and discuss our morphological matching approach. I will show the resulting 3D CRp density map and highlight the challenges in CR tomography and the current state of the project.