Stellar mass-to-light ratio gradients in galaxies: correlations with mass

TL;DR

This study investigates how stellar mass-to-light ratio gradients vary across different galaxy types and masses, revealing correlations with color and age, and providing insights into galaxy formation and dark matter estimation.

Contribution

It presents a comprehensive analysis of M/L gradients in local galaxies, linking them to color and age variations, and highlighting their dependence on galaxy mass and type.

Findings

M/L gradients are strongly correlated with color gradients.

Late-type galaxies have steeper negative M/L gradients with increasing mass.

Early-type galaxies show a two-fold trend in M/L gradients around a characteristic mass.

Abstract

We analyze the stellar mass-to-light ratio (M/L) gradients in a large sample of local galaxies taken from the Sloan Digital Sky Survey, spanning a wide range of stellar masses and morphological types. As suggested by the well known relationship between M/L ratios and colors, we show that M/L gradients are strongly correlated with colour gradients, which we trace to the effects of age variations. Stellar M/L gradients generally follow patterns of variation with stellar mass and galaxy type that were previous found for colour and metallicty gradients. In late-type galaxies M/L gradients are negative, steepening with increasing mass. In early-type galaxies M/L gradients are shallower while presenting a two-fold trend: they decrease with mass up to a characteristic mass of \M* \sim 10^10.3 M_sun and increase at larger masses. We compare our findings with other analyses and discuss some implications for galaxy formation and for dark matter estimates.