Analysis of spatially resolved stellar populations and emission line properties in nearby galaxies with J-PLUS data. II-Results for the M51 group and first comparison with the M101 group

TL;DR

This study uses J-PLUS survey data to analyze spatially resolved stellar populations and emission lines in nearby galaxy groups, revealing environmental effects on galaxy evolution and demonstrating the survey's potential for detailed galaxy analysis.

Contribution

It applies a consistent methodology to the M51 group, compares it with the M101 group, and highlights the impact of environment and interactions on galaxy properties.

Findings

M51a shows active star-forming spiral arms, M51b is a retired galaxy.

M63 exhibits asymmetries indicating outside-in quenching.

M51 group shows signs of advanced dynamical evolution.

Abstract

We characterize the spatially resolved stellar population and emission-line properties of galaxies in the M51 group using the same methodology previously applied to the M101 group, aiming to understand how environmental processes shape galaxy properties across different groups. Properties are derived by applying the \textsc{AlStar} spectral fitting code to multi-band datacubes from the Javalambre Photometric Local Universe Survey (J-PLUS). We present spatially resolved maps of the main stellar population and emission-line properties for the M51 group galaxies. The interacting pair M51a/b displays clearly distinct properties: M51a shows prominent star-forming spiral arms, while its companion is essentially an early-type retired galaxy. M63 exhibits asymmetries in stellar age, dust attenuation, and H$_\alpha$ equivalent width, consistent with outside-in quenching likely related to a past interaction. Relations between physical properties and stellar mass surface density ($\Sigma_\star$) were investigated. The age-$\Sigma_\star$ and nebular metallicity-$\Sigma_\star$ relations are flatter than those in the M101 group. In addition, all galaxies align with the resolved star-forming main sequence, except M51b, which shows the properties of a retired galaxy. Overall, the M51 group displays signatures of more advanced dynamical evolution than the M101 group. This is evidenced by flattened age and nebular metallicity gradients, enhanced dust content, and signs of environmental quenching in some members. In contrast, the less dynamically evolved M101 group largely preserves its inside-out formation signatures. While these results suggest that group mass and interactions influence galaxy evolution even in low-mass environments, the comparison of two systems remains limited by small-number statistics. This study highlights the potential of J-PLUS data for IFS-like analyses of nearby galaxies.