Central Velocity Dispersion as the Primary Driver of Abundance Patterns in Quenched Galaxies

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Abstract The element abundances of galaxies provide crucial insights into their formation and evolution. Using high-resolution integral field unit data from the Mapping Nearby Galaxies at Apache Point Observatory survey, we analyze the central spectra (0–0.5 R e) of 1185 quenched galaxies (z = 0.012−0.15) to study their element abundances and stellar populations. We employ the full-spectrum fitting code alf to derive stellar ages and element abundances from synthetic spectra and empirical libraries. Our key findings are: (1) the central velocity dispersion (σ *) is the most effective parameter correlating with the (relative) element abundances, especially [Na/Fe], [Mg/Fe], [C/Fe], and [N/Fe], outperforming M * and M */R e; (2) when binned by σ *, the relative abundances of Na, Mg, C, and N remain stable across different formation times (T form), suggesting these elements are primarily influenced by the burstiness of star formation (traced by σ *) rather than prolonged evolutionary processes; and (3) Fe and Ca show little variation with σ *, indicating weaker sensitivity to σ *-driven processes. However, T form has a global influence on all elements, contributing to their overall chemical evolution, although this is secondary to σ * for most elements. These results support the primary role of σ * in shaping the abundance patterns, likely stemming from the connection with central massive black holes and possibly also that with dark matter halos, which influences the burstiness of star formation histories.

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