The Fornax3D project: The environmental impact on gas metallicity gradients in Fornax cluster galaxies

Abstract

The role played by environment in galaxy evolution is a topic of ongoing debate among astronomers. There has been little success in elucidating the degree to which environment can alter, re-shape, or drive galaxy evolution, that is, using either observations or simulations. However, our knowledge of the effect of environment on gas metallicity gradients remains limited. Here we present our analysis of the gas metallicity gradients for a sample of ten Fornax cluster galaxies observed with MUSE as part of the Fornax3D project. We used detailed maps of emission lines to determine precise values of gas metallicity and metallicity gradients. The integrated gas metallicity of our Fornax cluster galaxies shows slightly higher metallicities (∼0.045 dex) in comparison to a control sample. In addition, we find signs of a mass and metallicity segregation from the center to the outskirts of the cluster. By comparing our Fornax cluster metallicity gradients with a control sample we find a general median offset of ∼0.04 dex/Re, with eight of our galaxies showing flatter or more positive gradients. The intermediate infallers in our Fornax sample show more positive gradients with respect to the control sample. We find no systematic difference between the gradients of recent and intermediate infallers when considering the projected distance of each galaxy to the cluster center. To identify the origin of the observed offset in the metallicity gradients, we performed a similar analysis with data from the TNG50 simulation. We identify 12 subhalos in Fornax-like clusters and compared their metallicity gradients with a control sample of field subhalos. This exercise also shows a flattening in the metallicity gradients for galaxies in Fornax-like halos, with a median offset of ∼0.05 dex/Re. We also analyzed the merger history, Mach numbers (ℳ), and ram pressure stripping of our TNG50 sample. We conclude that the observed flattening in metallicity gradients is likely due to a combination of galaxies traveling at supersonic velocities (ℳ > 1), which are experiencing high ram pressure stripping and flybys.

Metal-THINGS: Association and optical characterization of supernova remnants with H I holes in NGC 6946

“…The gas metallicity estimated through strong emission lines give important clues on the physical properties of the ISM and formation and growth of galaxies. Negative gas metallicity gradients are widely found in late-type galaxies in the local universe (e.g., Zaritsky, Kennicutt & Huchra 1994;Pilyugin et al 2004;Moustakas et al 2010;Pilyugin et al 2014;Belfiore et al 2017;Lara-López et al 2022). Such negative gradients are consistent with an inside-out growth scenario of the discs (e.g.…”

Environmental Dependence of Type Ia Supernovae in Low-redshift Galaxy Clusters

“…Metallicity has been suggested as a factor in SN Ia variation (D'Andrea et al 2011;Childress et al 2013), and the deep gravitational potential well at the centers of galaxy clusters should retain metals better than field quiescent galaxies. However, studies of low-redshift cluster galaxies show they are only slightly more metal-rich (0.05 dex) than field counterparts (Ellison et al 2009;Lara-López et al 2022). Observations of the intracluster medium do show a metal enhancement near low-z cluster centers (Lovisari & Reiprich 2019), but the metals escape the galaxies (and subsequent generations of stars) similarly to field quiescent galaxies.…”

Brought to Light. III. Colors of Disk and Clump Substructures in Dwarf Early-type Galaxies of the Fornax Cluster

“…As such, we believe that our analysis would deeply benefit if supplemented with spectroscopic data, which would provide additional insight on the stellar populations (and also the dynamics) of the galaxies. Several studies have already shown how Integral Field Unit spectroscopy can be used to thoroughly dissect and extract the properties of galaxies of the Fornax cluster (Iodice et al 2019;Johnston et al 2020;Lara-López et al 2022), including dwarf galaxies. This is something we would like to incorporate in our future work.…”