Gas Inflow and Outflow Histories in Disk Galaxies as Revealed From Observations of Distant Star-Forming Galaxies

Abstract

We investigate gas inflow and outflow histories in Milky Way-like disk galaxies, to get new insights into the baryonic processes in galaxy formation and evolution. For this purpose, we solve the equations for the evolutions of the surface mass densities of gas and metals at each radius in a galactic disk, based on the observed structural properties of distant star-forming galaxies, including the redshift evolution of their stellar mass distribution, their scaling relation between the mass of baryonic components, star formation rate (SFR) and chemical abundance, as well as the supposed evolution of their radial metallicity gradients (RMGs). We find that the efficiency of gas inflow for a given SFR decreases with time and that the inflow rate is always nearly proportional to the SFR. For gas outflow, although its efficiency for a given SFR is a decreasing function of time, similarly to gas inflow, the outflow rate is not necessarily proportional to the SFR and the relation between the outflow rate and SFR strongly depends on the evolution of the adopted RMG. We also find that the results on the outflow rate can be reproduced in the framework of momentum-driven (energy-driven) wind mechanism if the RMG is steepening (flattening) with time. Therefore if the well measured RMGs and their evolution for Milky Way-like galaxies are obtained from future observations, then our results will be useful to constrain the main driving mechanism for their galactic outflows.

BIMODIAL DISTRIBUTION OF GALACTIC DISK STARS ON THE [α/Fe]–[Fe/H] PLANE AS POSSIBLE EVIDENCE OF DISCONTINUOUS RADIAL MIGRATION HISTORY

“…According to previous works on chemical evolution models applied to several observational results of extra-galactic star-forming galaxies, the outflow-mass loading factor increases with increasing redshift (e.g. Yabe et al 2015;Toyouchi & Chiba 2015). Therefore, our time-independent mass loading factor may be regarded as an time-averaged one, although it actually changes with time.…”

ALMA view of the 12C/13C isotopic ratio in starburst galaxies

“…A top-heavy stellar initial mass function could make this effect even more pronounced (e.g., Romano et al 2017;Zhang et al 2018). The inflow scenario discussed for starbursts may even lead to higher 12 C/ 13 C ratios for ultraluminous infrared galaxies (ULIRGs) since such objects have more powerful inflows (e.g., Toyouchi & Chiba 2015;Yabe et al 2015;Falstad et al 2017). Indeed, ULIRGs have not only a higher 12 C/ 13 C ratio, but are also deviating from the canonical mass-metallicity relation in the sense of having a lower metallicity for their mass or a higher mass for their metallicity (Pereira-Santaella et al 2017).…”

Hadronic Interactions of Energetic Charged Particles in Protogalactic Outflow Environments and Implications for the Early Evolution of Galaxies

“…A CR-advecting outflow may also have the ability to heat external gas and thus reduce (or even halt) gas inflow to the host galaxy. In turn, this may hamper star-formation by depriving the system of the cool, inflowing gases potentially responsible for driving the starburst phase (Kereš et al 2005;Dayal et al 2013;Lu et al 2015;Toyouchi & Chiba 2015;Yabe et al 2015;Dayal & Ferrara 2018), and this would lead to quenching or a reduction of the star-formation rate of the system by 'strangulation' (e.g. Peng et al 2015) -see also the following section 5, where we demonstrate the impact CR containment and subsequent outflow advection may have in the recently observed high-redshift galaxy MACS1149-JD1 (Zheng et al 2012;Hashimoto et al 2018).…”