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

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.

Keywords

• Stellar populations
• Chemical abundances
• Early-type galaxies
• Galaxy evolution