Fountain-driven gas accretion feeding star formation over the disc of NGC 2403

ABSTRACT We use a dynamical model of galactic fountain to study the neutral extraplanar gas (EPG) in nearby spiral galaxy NGC 2403. have modelled EPG as combination material ejected from disc by stellar feedback (i.e. fountain) and accreting inner circumgalactic medium (CGM). This accretion is expected occur because cooling/condensation hot CGM (corona) triggered fountain. Our reproduces distribution kinematics H i emission 2403 remarkably well suggests total mass $4.7^{+1.2}_{-0.9}\times 10^8\, \mathrm{M_\odot }$, with typical scale height around 1 kpc vertical gradient rotation velocity $-10.0\pm 2.7\, \mathrm{km\, s^{-1}\, kpc^{-1}}$. The best-fitting requires characteristic outflow $50\pm 10\, s^{-1}}$. outflowing starts out mostly ionized only becomes later trajectory. rate condensation inferred 0.8 $\mathrm{M}_\odot \, \mathrm{yr}^{-1}$, approximately equal star-formation this (0.6 \mathrm{yr}^{-1}$). show that profile, which peaks at radius about 4.5 kpc, predicts growth compatible observed value. results indicate fountain-driven corona likely mechanism sustain star formation, inside-out local galaxies.