Abstract

Contributed Talk - Splinter DustEvol

Thursday, 12 September 2024, 15:00   (S12)

Dust destruction at high Galactic altitudes

Evgeniia Sivkova, Ilse De Looze
Ghent University, Krijgslaan 281 – S9, B-9000 Ghent, Belgium

Various observations reveal the presence of dust at high galactic altitudes in the vicinity of most disc galaxies, including the Milky Way. Apparently, there are some dust removal processes that effectively transport dust grains from galactic discs to circumgalactic space as conditions for dust formation are absent. The most obvious mechanism of dust expulsion from disc galaxies is the grain entrainment in motion by the galactic wind. This mechanism is indeed efficient in galaxies with intense star formation and/or active nuclei. However, extraplanar dust is also observed in galaxies exhibiting low rates of the star formation. The sweeping of dust by the stellar radiation pressure is often mentioned as an important dust removal factor for galaxies both with and without active star formation. Apparently, both supernovae and radiation pressure are important factors in the creation of dust structures above spiral disks. We model dust motion in the Galaxy taking into account the combined action of radiation pressure, gravity, and gas drag, along with sputtering and shattering processes. We estimate a range of grain sizes that can get into intergalactic space, being swept by the stellar radiation pressure.