Local and large-scale effects on the astrophysics of void galaxies

Abstract

Galaxies in cosmic voids have been reported with properties related to a delayed evolution compared to the rest of the Universe. These characteristics reflect the interaction of galaxies with the environment. However, it is not clear the degree of influence of the large-scale structure on the properties of void galaxies or, if these are only influenced by the low local density around them typical of these regions. In this article we identified cosmic voids in the SDSS-DR16 and studied the g-r colour, star formation rate, and concentration of galaxies. We identified galaxy groups to characterise the local environment and studied the properties of galaxies as a function of total and stellar masses, separately analyzing those in voids and the general sample. Our results show that galaxies that inhabit haloes of a given mass (below ∼ 1013.5M⊙), are bluer, have a higher star formation rate and are less concentrated when the host halo is inside voids compared to other regions. For larger halo masses, the trend disappears. We also analyse whether the properties of galaxies are sensitive to the type of voids that inhabit. This is done by separating voids embedded in overdense regions (S-type) from those that asymptotically converge to the average density of the universe (R-type). We found that galaxies in R-type voids are bluer, with higher SFR and less concentration than in S-type voids. Our results indicate some degree of correlation of galaxy properties with the large-scale environment provided by voids, suggesting possible second-order mechanisms in galaxy evolution.

Star Formation and Dust in the Cosmic Web

“…Details of the algorithm's application to observational samples are provided in Ruiz et al (2019). Specifically, in this work, the void identification is the same as in Rodríguez-Medrano et al (2023; see their Section 2.1). Voids are identified in a volume-complete sample with limiting redshift z = 0.1 and maximum absolute magnitude in the r band, M h 5 log 20 r -=-, extracted from the main SDSS region.…”

“…On the other hand, galaxies and their local environments are embedded in different large-scale environments (10-100 Mpc) of the cosmic web (like cosmic voids, walls, and filaments). However, the impacts of such environments on galaxy formation and evolution remain a matter of debate (e.g., Alfaro et al 2022;Rodríguez-Medrano et al 2023;Wang et al 2023). In this work, we employ the term environment to denote the large-scale environment, unless stated otherwise.…”