Traces of the evolution of cosmic void galaxies: An integral field spectroscopy-based analysis

Context. Galaxies in the most underdense regions of the Universe, known as cosmic voids, exhibit astrophysical properties that suggest a distinct evolutionary path compared to galaxies in denser environments. Numerical simulations indicate that the assembly of void galaxies occurs later, leading to galaxies with younger stellar populations, low metallicities, and high gas content in their halos, which provides the fuel to sustain elevated star formation activity. Aims. Our objective in this work is to test these numerical predictions using observational data by comparing galaxies in voids with galaxies in non-void environments. Methods. We used voids identified in the SDSS data and selected galaxies from the MaNGA survey, which offers integral field spectroscopy (IFS) for each galaxy. This IFS data allows for state-of-the-art modeling of their stellar populations. We separated the galaxies into void and non-void samples, mimicked the magnitude distribution, and compared their integrated astrophysical properties, as well as the metallicity and age profiles, through a stacking technique. We analyzed early-type galaxies (ETGs) and late-type galaxies (LTGs) separately. Results. We find that void galaxies tend to host younger and less metal-rich stellar populations. This trend is observed both as a function of mass and in samples with matched magnitude distributions. With respect to the gas mass, we do not find differences across environments. When dividing galaxies into ETGs and LTGs, we observe that ETGs show negative gradients in both age and metallicity, with void galaxies consistently appearing younger and less metal-rich. For LTGs, age gradients are also negative, indicating younger populations in void galaxies. However, we do not find statistically significant differences in the stellar metallicity gradients between void and non-void environments. Conclusions. Our results show how the astrophysical properties of galaxies in voids differ from those of galaxies in the rest of the Universe. This suggests that the void environment plays a role in the evolution of its galaxies, delaying their assembly and growth.