Alma Co-Cavity

Scaling relations involving star formation rates (SFRs), molecular gas mass, and stellar mass are key to understanding galaxy evolution and have previously been explored at resolved scales. However, they have not been examined with particular emphasis on the large-scale environments (LSEs). In this work, we study the resolved Schmidt-Kennicutt relation (rSK), molecular gas main sequence (rMGMS), and star-forming main sequence (rSFMS) in a sample of 41 void galaxies (VGs) residing in the least dense regions of the Universe. We used high-resolution interferometric CO(1–0) data and optical integral field unit data from the ALMA CO-CAVITY and CAVITY surveys at scales of 2.″5 (0.8–2.1 kpc) to study these relations for both the full sample and individual galaxies in voids. We fit the relations and find a similar parametrisation to that used for galaxies from all LSEs. However, the rMGMS is the tightest of the three relations ( σ rMGMS = 0.16 dex, σ rSK = 0.21 dex, and σ rSFMS = 0.24 dex), unlike in other samples. We find that a large source of deviations in the relations comes from galaxy-to-galaxy variations. However, the rMGMS is less affected by these variations. The rMGMS may arise from the concentration of molecular gas within the gravitational potential set by the stellar content and dark matter. We hypothesise that deviations from the rMGMS trace changes in the gravitational potential occurring on longer timescales, whereas deviations in the rSK and the rSFMS are driven by more rapid variations in the SFR. This distinction is particularly relevant for our sample because the 41 ALMA CO-CAVITY VGs are generally more isolated than galaxies in other LSEs and therefore are less affected by events that can significantly alter the gas distribution or trigger SF on short timescales. In this sense, the rMGMS is likely the most stable of these relations over time.