Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 10: Gamma astronomy 1
T 10.8: Talk
Monday, March 4, 2024, 17:45–18:00, Geb. 30.22: kl. HS A
Spatially Coherent 3D Distributions of HI and CO in the Milky Way — •Laurin Söding1, Philipp Mertsch1, and Vo Hong Minh Phan2 — 1Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University, 52056 Aachen, Germany — 2LERMA, Sorbonne University
The spatial distribution of the gaseous components of the Galaxy is of great importance for interpreting and modelling cosmic ray data and diffuse emission. Reconstructing interstellar gas from doppler-shifted line emission requires knowledge of gas velocities and generally suffers from distance ambiguities.
We overcome these issues by reconstructing the posterior distribution of 3D HI and CO gas densities and velocities in a common Bayesian inference scheme. We explicitly enforce a spatially coherent structure by means of modelling the 3D fields as correlated (log)normal random fields.
For the first time, we include the modelling of absorption effects, which are especially important for the usually optically thick CO emission lines. We also improve on previous reconstructions by promoting the galactic velocity field and the emission line widths to the set of reconstructed fields, and further constrain their values with complementary data from galactic masers.
We provide a spatially coherent large-scale picture of the 3D distribution of gas in the Galaxy and illustrate the value of these maps in predicting diffuse gamma-ray emission.
Keywords: Bayesian Inference; Interstellar Medium; Milky Way; Gas Distribution; Gamma-Rays