Vol. 606
In section 6. Interstellar and circumstellar matter

Three-dimensional mapping of the local interstellar medium with composite data

by L. Capitanio, R. Lallement, J.L. Vergely, M. Elyajouri, and A. Monreal-Ibero, A&A 606, A65


Obtaining a detailed picture of the 3-D structure of even the local interstellar medium remains a major challenge. The fine structure, averaged out on larger scales, has thus far been the only unambiguous view we have of how the gas and dust are structured on scales of tens of parsecs. The ambitious, successful aim of the present study is to cover lines of sight of up to a few kiloparsecs using stellar parallax and proper motions of background light sources with high accuracy, using the first Gaia data release. The authors do this by combining different measures for the two diffuse components, using a near infrared absorption band (DIB) to obtain extinction (reddening) estimates. They use a novel Bayesian inversion method to reconstruct the fine structure from tens of thousands of DIB measurements of profiles and velocities, with the constraint of maximum extinction in any direction. The structures thus obtained, both clouds and vacancies, can then be compared with multiwavelength data from the UV and XR for further refinement.