Abstract
We study the evolution of galactic bars using a suite of very high-resolution zoom-in cosmological simulations of galaxies at z ∼ 9-2. Our models were chosen to lie within similar-mass dark matter (DM) halos, log(M vir/M ⊙) ∼ 11.65 ± 0.05, at z = 6, 4, and 2, in high- and low-overdensity environments. We apply two galactic wind feedback mechanisms for each model. All galaxies develop subkiloparsec stellar bars differing in their properties. We find that (1) the high-z bars form in response to various perturbations: mergers, close flybys, cold accretion inflows along the cosmological filaments, etc.; (2) these bars account for the large mass fraction of galaxies; (3) bars display large corotation-to-bar size ratios, are weaker compared to their low-redshift counterparts by measuring their Fourier amplitudes, and are very gas-rich; (4) their pattern speed does not exhibit monotonic decline with time owing to braking against DM, as at low z; (5) bar properties, including their stellar population (star formation rates and metal enrichment), depend sensitively on prevailing feedback; and (6) bars can weaken substantially during cosmological evolution, becoming weak oval distortions—hence bars are destroyed and reformed multiple times, unlike their low-z counterparts. In all cases, bars in our simulations have been triggered by interactions. In summary, not only do stellar bars appear to be a contemporary phenomenon, but based on increased frequency of mergers, flybys, and the strength of cold accretion flows at high z, we also expect them to be ubiquitous at redshifts ≳2—the epoch of rapid galaxy growth and larger stellar dispersion velocities.
| Original language | English |
|---|---|
| Article number | 52 |
| Journal | Astrophysical Journal |
| Volume | 934 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 1 2022 |
Bibliographical note
Publisher Copyright:© 2022. The Author(s). Published by the American Astronomical Society.
Funding
We thank Phil Hopkins for providing us with the latest version of GIZMO. We are grateful to Alessandro Lupi for his help with GIZMO. We also thank Xingchen Li for sharing some of the analysis software. I.S. is grateful for generous support from the International Joint Research Promotion Program at Osaka University. This work has also been partially supported by Hubble Theory grant HST-AR-14584 and by JSPS KAKENHI grant 16H02163 (to I.S.). The STScI is operated by the AURA, Inc., under NASA contract NAS5-26555. E.R.D. acknowledges support of the Collaborative Research Center 956, subproject C4, funded by the Deutsche Forschungsgemeinschaft (DFG). Simulations have been performed using generous allocation of computing time on the XSEDE machines under NSF grant TG-AST190016 and by the University of Kentucky Lipscomb Computing Cluster. We thank Vikram Gazula at the Center for Computational Studies at the University of Kentucky for his continuous help. We thank Phil Hopkins for providing us with the latest version of GIZMO. We are grateful to Alessandro Lupi for his help with GIZMO. We also thank Xingchen Li for sharing some of the analysis software. I.S. is grateful for generous support from the International Joint Research Promotion Program at Osaka University. This work has also been partially supported by Hubble Theory grant HST-AR-14584 and by JSPS KAKENHI grant 16H02163 (to I.S.). The STScI is operated by the AURA, Inc., under NASA contract NAS5-26555. E.R.D. acknowledges support of the Collaborative Research Center 956, subproject C4, funded by the Deutsche Forschungsgemeinschaft (DFG). Simulations have been performed using generous allocation of computing time on the XSEDE machines under NSF grant TG-AST190016 and by the University of Kentucky Lipscomb Computing Cluster. We thank Vikram Gazula at the Center for Computational Studies at the University of Kentucky for his continuous help.
| Funders | Funder number |
|---|---|
| Phil Hopkins | |
| University of Kentucky Lipscomb Computing Cluster | |
| Vikram Gazula | |
| National Science Foundation Arctic Social Science Program | TG-AST190016 |
| National Science Foundation Arctic Social Science Program | |
| National Aeronautics and Space Administration | NAS5-26555 |
| National Aeronautics and Space Administration | |
| Deutsche Forschungsgemeinschaft | |
| Japan Society for the Promotion of Science | 16H02163 |
| Japan Society for the Promotion of Science | |
| Osaka University | HST-AR-14584 |
| Osaka University |
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science