Metallicity Gradients in Modern Cosmological Simulations II: The Role of Bursty Versus Smooth Feedback at High-Redshift
Authors
Alex M. Garcia
Paul Torrey
Aniket Bhagwat
Xuejian Shen
Mark Vogelsberger
William McClymont
Jaya Nagarajan-Swenson
Sophia G. Ridolfo
Peixin Zhu
Dhruv T. Zimmerman
Oliver Zier
Sarah Biddle
Arnab Sarkar
Priyanka Chakraborty
Ruby J. Wright
Kathryn Grasha
Tiago Costa
Laura Keating
Rahul Kannan
Aaron Smith
Enrico Garaldi
Ewald Puchwein
Benedetta Ciardi
Lars Hernquist
Lisa J. Kewley
Abstract
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.
