Kavli Affiliate: Yingjie Peng
| First 5 Authors: Cheqiu Lyu, Enci Wang, Hongxin Zhang, Yingjie Peng, Xin Wang
| Summary:
Using spatially resolved spectroscopic data from the MaNGA sample, we
investigate the parameters influencing the radial gradients of gas-phase
metallicity ($nablalog(mathrm{O/H})$), to determine whether disk formation
is primarily driven by coplanar gas inflow or by the independent evolution of
distinct regions within the disk. Our results show that $nabla
log(mathrm{O/H})$ strongly correlates with local gas-phase metallicity at a
given stellar mass, with steeper gradients observed in metal-poorer disks. This
trend supports the coplanar gas inflow scenario, wherein the gas is
progressively enriched by in situ star formation as it flows inward. In
contrast, the radial gradient of stellar mass surface density shows very weak
correlations with $nabla log(mathrm{O/H})$, which is inconsistent with the
independent evolution mode, where gas inflow, star formation, and metal
enrichment occur independently within each annulus of the disk. Furthermore, we
find that $nabla log(mathrm{O/H})$ is also closely correlated with an
indicator of local gas turbulence $sigma_{mathrm{gas}}/R_{mathrm{e}}$,
highlighting the competing roles of turbulence and coplanar inflow in shaping
metallicity gradients. Our results provide indirect observational evidence
supporting coplanar gas inflow as the driving mechanism for disk evolution.
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