Neutral hydrogen in galactic fountains

Abstract

Simulations of an isolated Milky Way-like galaxy, in which supernovae power a galactic fountain, reproduce the observed velocity and 21cm brightness statistics of galactic neutral hydrogen (HI). The simulated galaxy consists of a thin HI disk, similar in extent and brightness to that observed in the Milky Way, and extra-planar neutral gas at a range of velocities due to the galactic fountain. Mock observations of the neutral gas resemble the HI flux measurements from the Leiden-Argentine-Bonn (LAB) HI, survey, including a high-velocity tail which matches well with observations of high-velocity clouds. The simulated high-velocity clouds are typically found close to the galactic disk, with a typical line-of-sight distance of 13kpc from observers on the solar circle. The fountain efficiently cycles matter from the centre of the galaxy to its outskirts at a rate of around 0.5 M_sun/yr

5 pages, 5 figures. Accepted for publication in MNRAS letters

References in corpus (5)

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• Relics of structure formation: extra-planar gas and high-velocity clouds around the Andromeda Galaxy
• The orientations of molecular clouds in the outer Galaxy: Evidence for the scale of the turbulence driver ?
• The thickness of HI in galactic discs under MOND: theory and application to the Galaxy
• Storm fronts over galaxy discs: Models of how waves generate extraplanar gas and its anomalous kinematics
• A Spitzer-MIPS search for dust in compact high-velocity HI clouds