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We present a sample of 17 objects from the CALIFA survey where we find initial evidence of galactic winds based on their off-axis ionization properties. We identify the presence of outflows using various optical diagnostic diagrams [e.g. EW(H α), [N  ii ]/H α, [S  ii ]/H α, [O  i ]/H α line-ratio maps]. We find that all 17 candidate outflow galaxies lie along the sequence of active star formation in the M⋆ versus star-formation rate (SFR) diagram, without a clear excess in the integrated SFR. The location of galaxies along the star-formation main sequence does not influence strongly the presence or not of outflows. The analysis of the SFR density (ΣSFR) reveals that the CALIFA sources present higher values when compared with normal star-forming galaxies. The strength of this relation depends on the calibrator used to estimate the SFR. This excess in ΣSFR is significant within the first effective radius supporting the idea that most outflows are driven by processes in the inner regions of a galaxy. We find that the molecular gas mass density (Σgas) is a key parameter that plays an important role in the generation of outflows through its association with the local SFR. The canonical threshold reported for the generation of outflows – ΣSFR > 0.1 |$\mathrm{M}_\odot \, \mathrm{yr}^{-1} \, \mathrm{kpc}^{-2}$| – is only marginally exceeded in our sample. Within the Kennicutt–Schmidt diagram we propose a domain for galaxies hosting starburst-driven outflows defined by |$\Sigma _{\rm SFR}\gt 10^{-2} \, \mathrm{M}_\odot \, \mathrm{yr}^{-1} \, \mathrm{kpc}^{-2}$| and |$\Sigma _\mathrm{gas}\gt 10^{1.2} \, \, \mathrm{M}_\odot \, \mathrm{pc}^{-2}$| within a central kiloparsec region. [ABSTRACT FROM AUTHOR]

We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, gas surface density and gas-phase metallicity, and show that these parameters form a tight relation independent of initial gas density and time.We show that, with canonical values of model parameters, this predicted relation match the observed one well. In addition, we briefly describe a pathway to improving the current semi-analytic models of galaxy formation by incorporating the local leaky-box model in the cosmological context, which can potentially explain simultaneously multiple properties of Milky Way-type disc galaxies, such as the size growth and the global stellar mass–gas metallicity relation. [ABSTRACT FROM AUTHOR]