A deep study of the spiral galaxy W2246f

Le résumé fourni par la source

Aims. In this era of large surveys and statistical studies of galaxies, the beauty in the details of individual galaxies is often lost. In this paper we present a deep study of the spiral galaxy W2246f with MUSE, exploring the spatially resolved stellar and ionised gas properties to understand how it formed and evolved over time. The unusually deep observations of this galaxy with MUSE give us a rare opportunity to study this phenomenon with a better spatial resolution than can normally be achieved with the current IFU surveys of galaxies at a similar redshift (z ∼ 0.09). Methods. We analyse the stellar and gas kinematics, as well as the spatially resolved stellar populations and gas properties, including gas metallicity and the dominant ionisation sources. The derived properties include the stellar mass, radial profiles of luminosity- and mass-weighted mean ages and metallicities, and ionised gas characteristics such as E(B − V), Hα extinction, dust-corrected Hα flux, oxygen abundance using the O3N2 calibrator, Hα luminosity, and the Hα-based star formation rate. Results. Analysis of the stellar populations revealed a negative metallicity gradient, and the mass-weighted ages showed uniformly flat ages across the disc while the luminosity-weighted ages show a negative gradient. We find that the gas metallicity and star formation rate density also drop in the central region of the galaxy where the older luminosity-weighted stellar populations are found. Analysis of the WHAN and WHaD diagrams reveal that in fact the central region is retired, while the rest of the disc is star-forming. Conclusions. We conclude that W2246f is a nice example of a central low-ionisation emission-line region (cLIER) galaxy, where the central kpc is dominated by old, metal-poor stars with little star formation. The cLIER emission is primarily powered by hot evolved stars, while the rest of the disc displays ongoing star formation. These findings are consistent with a scenario of inside-out quenching.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.