Published January 1, 2025 | Version Published
Journal Article Open

Bar Formation and Destruction in the FIRE-2 Simulations

  • 1. ROR icon Flatiron Institute
  • 2. ROR icon Indian Institute of Astrophysics
  • 3. ROR icon Pondicherry University
  • 4. ROR icon New York University
  • 5. ROR icon University of Copenhagen
  • 6. ROR icon University of Pennsylvania
  • 7. ROR icon California Institute of Technology
  • 8. ROR icon University of California, Berkeley
  • 9. ROR icon Columbia University
  • 10. ROR icon University of California, Merced

Abstract

The physical mechanisms responsible for bar formation and destruction in galaxies remain a subject of debate. While we have gained valuable insight into how bars form and evolve from isolated idealized simulations, in the cosmological domain, galactic bars evolve in complex environments, with mergers and gas accretion events occurring in the presence of the turbulent interstellar medium with multiple star formation episodes, in addition to coupling with their host galaxies’ dark matter halos. We investigate the bar formation in 13 Milky Way–mass galaxies from the Feedback in Realistic Environments (FIRE-2) cosmological zoom-in simulations. 8 of the 13 simulated galaxies form bars at some point during their history: three from tidal interactions and five from internal evolution of the disk. The bars in FIRE-2 are generally shorter than the corotation radius (mean bar radius ∼1.53 kpc), have a wide range of pattern speeds (36–97 km s−1 kpc−1), and live for a wide range of dynamical times (2–160 bar rotations). We find that the bar formation in FIRE-2 galaxies is influenced by satellite interactions and the stellar-to-dark-matter mass ratio in the inner galaxy, but neither is a sufficient condition for bar formation. Bar formation is more likely to occur, with the bars formed being stronger and longer-lived, if the disks are kinematically cold; galaxies with high central gas fractions and/or vigorous star formation, on the other hand, tend to form weaker bars. In the case of the FIRE-2 galaxies, these properties combine to produce ellipsoidal bars with strengths A2/A0 ∼ 0.1–0.2.

Copyright and License

© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

This work was facilitated by the Pre-Doctoral Program of the Center for Computational Astrophysics at the Flatiron Institute; analysis was carried out on resources maintained by the Scientific Computing Core. The Flatiron Institute is supported by the Simons Foundation.

S.A. is grateful to the Simons Foundation for the support during the Pre-Doctoral Program from 2021 February to 2021 June.

Support for S.P. was provided by NASA through the NASA Hubble Fellowship grant #HST-HF2-51466.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. This work was supported by a research grant (VIL53081) from VILLUM FONDEN.

R.E.S. gratefully acknowledges support from the Simons Foundation as well as from NSF grant AST-2007232 and NASA grant 19-ATP19-0068.

Support for P.F.H. was provided by NSF Research Grants 1911233, 20009234, and 2108318, NSF CAREER grant 1455342, and NASA grants 80NSSC18K0562 and HST-AR-15800.

A.W. received support from: NSF via CAREER award AST-2045928 and grant AST-2107772; NASA ATP grant 80NSSC20K0513; and HST grants AR-15809, GO-15902, and GO-16273 from STScI.

E.C.C acknowledges the support for this work provided by NASA through the NASA Hubble Fellowship Program grant HST-HF2-51502 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555.

Numerical calculations were run on allocations AST21010 and AST20016, supported by the NSF and TACC, and NASA HEC SMD-16-7592.

Data Availability

The FIRE-2 simulations are publicly available (A. Wetzel et al. 2023) at http://flathub.flatironinstitute.org/fire. Additional FIRE simulation data are available at https://fire.northwestern.edu/data. A public version of the Gizmo code is available at http://www.tapir.caltech.edu/~phopkins/Site/GIZMO.html.

Software References

astropy (Astropy Collaboration et al. 201320182022), gizmo analysis (A. Wetzel & S. Garrison-Kimmel 2020b), halo analysis (A. Wetzel & S. Garrison-Kimmel 2020a), AGAMA (E. Vasiliev 2019), photutils (L. Bradley et al. 2020).

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Additional details

Related works

Is new version of
Discussion Paper: arXiv:2309.16811 (arXiv)

Funding

Simons Foundation
National Aeronautics and Space Administration
HST-HF2-51466.001-A
Space Telescope Science Institute
National Aeronautics and Space Administration
NAS5-26555
Villum Fonden
VIL53081
National Science Foundation
AST-2007232
National Aeronautics and Space Administration
19-ATP19-0068
National Science Foundation
1911233
National Science Foundation
20009234
National Science Foundation
2108318
National Science Foundation
1455342
National Aeronautics and Space Administration
80NSSC18K0562
National Aeronautics and Space Administration
HST-AR-15800
National Science Foundation
AST-2045928
National Science Foundation
AST-2107772
National Aeronautics and Space Administration
80NSSC20K0513
Space Telescope Science Institute
AR-15809
Space Telescope Science Institute
GO-15902
Space Telescope Science Institute
GO-16273
National Aeronautics and Space Administration
HST-HF2-51502

Dates

Submitted
2023-09-29
Accepted
2024-10-23
Available
2024-12-24
Published

Caltech Custom Metadata

Caltech groups
Astronomy Department, TAPIR, Walter Burke Institute for Theoretical Physics, Division of Physics, Mathematics and Astronomy (PMA)
Publication Status
Published