RSAA Colloquia / Seminars / Feast-of-Facts: Friday, 11 September 2015, 11:00-12:00; Duffield Lecture Theatre

Tomaz Zwitter

"Dynamical interstellar medium with Gaia and ground-based massive spectroscopic stellar surveys"

Diffuse interstellar bands (DIBs) and atomic lines are observed as interstellar absorptions in GALAH and other massive spectroscopic stellar surveys. By observing a given DIB toward many stars which are nearly in the same direction, but at different distances, one can reconstruct absorption sites along the line of sight. Joining observations in many directions on the sky finally leads to their spatial distribution, while measurement of radial velocities adds the fourth dimension for each interstellar absorption. In special cases a complete velocity vector can be reconstructed which makes the dynamical picture of the interstellar medium equivalent to the one collected for stars by Gaia.