Sophia G. Ridolfo | Searcharxiv

arXiv2026

Metallicity Gradients in Modern Cosmological Simulations II: The Role of Bursty Versus Smooth Feedback at High-Redshift

The distribution of gas-phase metals within galaxies encodes the impact of stellar feedback on galactic evolution. At high-redshift, when galaxies are rapidly assembling, feedback-driven outflows and turbulence can strongly reshape radial metallicity gradients. In this work, we use the FIRE-2, SPICE, Thesan and Thesan Zoom cosmological simulations -- spanning a range of stellar feedback from bursty (time-variable) to smooth (steady) -- to investigate how these feedback modes shape gas-phase metallicity gradients at $3 10^{9}~{\rm M_\odot}$. These results demonstrate that bursty stellar feedback provides sufficient turbulence to prevent strong negative gradients from forming, while smooth stellar feedback does not generically allow for efficient radial redistribution of metals thereby keeping gradients steep. Finally, we compare with recent observations, finding that the majority -- but, notably, not all -- of the observed gradients may favor a bursty stellar feedback scenario. In all, these results highlight the utility of high-resolution observations of gas-phase metallicity at high-redshift as a key discriminator of these qualitatively different feedback types.

astro-ph.GA↗

arXiv2024

DUVET: sub-kiloparsec resolved star formation driven outflows in a sample of local starbursting disk galaxies

We measure resolved (kiloparsec-scale) outflow properties in a sample of 10 starburst galaxies from the DUVET (Deep near-UV observations of Entrained gas in Turbulent galaxies) sample, using Keck/KCWI observations of H$β$ and [OIII]~$λ$5007. We measure $\sim460$ lines-of-sight that contain outflows, and use these to study scaling relationships of outflow velocity ($v_{\rm out}$), mass-loading factor ($η$; mass outflow rate per SFR) and mass flux ($\dotΣ_{\rm out}$; mass outflow rate per area) with co-located SFR surface density ($Σ_{\rm SFR}$) and stellar mass surface density ($Σ_{\ast}$). We find strong, positive correlations of $\dotΣ_{\rm out} \propto Σ_{\rm SFR}^{1.2}$ and $\dotΣ_{\rm out} \propto Σ_{\ast}^{1.5}$. We also find shallow correlations between $v_{\rm out}$ and both $Σ_{\rm SFR}$ and $Σ_{\ast}$. Our resolved observations do not suggest a threshold in outflows with $Σ_{\rm SFR}$, but rather we find that the local specific SFR ($Σ_{\rm SFR}/Σ_\ast$) is a better predictor of where outflows are detected. We find that outflows are very common above $Σ_{\rm SFR}/Σ_\ast\gtrsim 0.1$~Gyr$^{-1}$ and rare below this value. We argue that our results are consistent with a picture in which outflows are driven by supernovae, and require more significant injected energy in higher mass surface density environments to overcome local gravity. The correlations we present here provide a statistically robust, direct comparison for simulations and higher redshift results from JWST.

astro-ph.GA↗