What holes in the gas distribution of nearly face-on galaxies can tell us about the host disk parameters: the case of the NGC 628 South-East superbubble

Abstract

Here we explore the impact of all major factors, such as the non-homogeneous gas distribution, galactic rotation and gravity, on the observational appearance of superbubbles in nearly face-on spiral galaxies. The results of our 3D numerical simulations are confronted to the observed gas column density distribution in the largest South-East superbubble in the late-type spiral galaxy NGC 628. We make use of the star formation history inside the bubble derived from the resolved stellar population seen in the HST images to obtain its energy and demonstrate that the results of numerical simulations are in good agreement with the observed gas surface density distribution. We also show that the observed gas column density distribution constraints the gaseous disk scale height and the midplane gas density if the energy input rate could be obtained from observations. This implies that observations of large holes in the interstellar gas distribution and their stellar populations have the potential power to solve the midplane gas density - gaseous disk scale-height degeneracy problem in nearly face-on galaxies. The possible role of superbubbles in driving the secondary star formation in galaxies is also briefly discussed.Comment: Accepted for publication in Ap