Galactic fountains and outflows in star forming dwarf galaxies: ISM expulsion and chemical enrichment

Abstract

We investigated the impact of supernova feedback in gas-rich dwarf galaxies experiencing a low-to-moderate star formation rate, typical of relatively quiescent phases between starbursts. We calculated the long term evolution of the ISM and the metal-rich SN ejecta using 3D hydrodynamic simulations, in which the feedback energy is deposited by SNeII exploding in distinct OB associations. We found that a circulation flow similar to galactic fountains is generally established, with some ISM lifted at heights of one to few kpc above the galactic plane. This gas forms an extra-planar layer, which falls back to the plane in about $10^8$ yr, once the star formation stops. Very little or no ISM is expelled outside the galaxy system for the considered SFRs, even though in the most powerful model the SN energy is comparable to the gas binding energy. The metal-rich SN ejecta is instead more vulnerable to the feedback and we found that a significant fraction (25-80\%) is vented in the intergalactic medium, even for low SN rate ($7\times 10^{-5}$ - $7\times 10^{-4}$ yr${}^{-1}$). About half of the metals retained by the galaxy are located far ($z>$ 500 pc) from the galactic plane. Moreover, our models indicate that the circulation of the metal-rich gas out from and back to the galactic disk is not able to erase the chemical gradients imprinted by the (centrally concentrated) SN explosions.

19 pages, MNRAS accepted

References in corpus (7)

• Vertical structure of a supernova-driven turbulent magnetized ISM
• The Recent Star Formation Histories of M81 Group Dwarf Irregular Galaxies
• Star formation feedback and metal enrichment by SN Ia and SN II in dwarf spheroidal galaxies: the case of Draco
• Hydrodynamical simulations of Galactic fountains I: evolution of single fountains
• The Turbulent Interstellar Medium
• Modeling the chemical evolution of Omega Centauri using three-dimensional hydrodynamical simulations
• The star formation history of the Sculptor Dwarf Irregular Galaxy

Cited by in corpus (11)

• Accretion of pristine gas and dilution during the formation of multiple-population globular clusters
• The metal content of the hot atmospheres of galaxy groups
• Gas dynamics in dwarf galaxies as testbeds for dark matter and galaxy evolution
• The Galaxy Activity, Torus, and Outflow Survey (GATOS). (IV): Exploring Ionized Gas Outflows in Central Kiloparsec Regions of GATOS Seyferts
• The effect of the environment-dependent stellar initial mass function on the photometric properties of star-forming galaxies
• New Analytic Solutions for Galaxy Evolution II: Wind Recycling, Galactic Fountains and Late-Type Galaxies
• The observable properties of cool winds from galaxies, AGN, and star clusters -- II. 3D models for the multiphase wind of M82
• The Baryonic Collapse Efficiency of Galaxy Groups in the RESOLVE and ECO Surveys
• New chemical evolution analytical solutions including environment effects
• Boundary conditions in hydrodynamic simulations of isolated galaxies and their impact on the gas-loss processes
• Blueberry and Green Pea galaxies live in low density environments