2025/02/01 by Tathagata Pal, Pal, Tathagata, Guy Worthey +1
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Black Holes and Theoretical Physics #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2502.00531
openalex publication_date 2025/02/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We derive stellar population parameters and radial gradients within 0.65 Re for spatially resolved spectra of 2968 early-type galaxies from MaNGA, spanning stellar velocity dispersions (σ) of 50--340 km s-1. Light-weighted mean age and C, N, Na, Mg, and Fe abundances are obtained by inverting metallicity-composite stellar population models with isochrones that respond in Teff to individual element abundance changes. Globally, log(age) increases (∼0.53 dex per decade), [Fe/H] declines slightly (∼-0.06 dex per decade), and [X/Fe] for light elements rises (0.19--0.37 dex per decade for logσ< 2.0 but steepens to nearly double slope for logσ> 2.0) with logσ. [Fe/H] peaks at logσ∼ 2.0 and falls on either side. Light-element [X/Fe] anticorrelates with [Fe/H] (∼-0.1 dex per decade). Astrophysical scatter is largest in low-σ galaxies, especially for Fe and N. Internally, age gradients are nearly flat in low-σ galaxies and slightly negative in high-σ systems (∼-0.04 dex per decade). [Fe/H] radial gradients steepen from -0.06 dex per decade to -0.15 dex per decade across σ, while light elements (except Na) show ∼-0.03 dex per decade gradients. Scatter in gradients peaks in high-σ galaxies, most strongly for Fe (∼0.23 dex), suggesting comparable numbers of inside-out and outside-in formation. A near-zero (∼-0.03) age and light-element gradient plus mild [Fe/H] gradients supports hierarchical merging for ETG evolution. Simulations match the observed age structure, slope change at logσ∼ 2.0, and flat gradients, though they overpredict absolute abundances.