CaltechAUTHORS
Published October 2023 | Version Published
Journal Article Metadata-only

What causes the formation of discs and end of bursty star formation?

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon Northwestern University
  • 3. ROR icon University of California, Irvine
  • 4. ROR icon Carnegie Observatories
  • 5. ROR icon Rutgers, The State University of New Jersey
  • 6. ROR icon University of California, Berkeley
  • 7. ROR icon University of California, San Diego
  • 8. ROR icon Tel Aviv University
  • 9. ROR icon California State Polytechnic University
  • 10. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 11. ROR icon University of California, Merced
  • 12. ROR icon Pomona College
  • 13. ROR icon The University of Texas at Austin
  • 14. ROR icon Princeton University

Abstract

As they grow, galaxies can transition from irregular/spheroidal with ‘bursty’ star formation histories (SFHs), to discy with smooth SFHs. But even in simulations, the direct physical cause of such transitions remains unclear. We therefore explore this in a large suite of numerical experiments re-running portions of cosmological simulations with widely varied physics, further validated with existing FIRE simulations. We show that gas supply, cooling/thermodynamics, star formation model, Toomre scale, galaxy dynamical times, and feedback properties do not have a direct causal effect on these transitions. Rather, both the formation of discs and cessation of bursty star formation are driven by the gravitational potential, but in different ways. Disc formation is promoted when the mass profile becomes sufficiently centrally concentrated in shape (relative to circularization radii): we show that this provides a well-defined dynamical centre, ceases to support the global ‘breathing modes’ that can persist indefinitely in less-concentrated profiles and efficiently destroy discs, promotes orbit mixing to form a coherent angular momentum, and stabilizes the disc. Smooth SF is promoted by the potential or escape velocity Vesc (not circular velocity Vc) becoming sufficiently large at the radii of star formation that cool, mass-loaded (momentum-conserving) outflows are trapped/confined near the galaxy, as opposed to escaping after bursts. We discuss the detailed physics, how these conditions arise in cosmological contexts, their relation to other correlated phenomena (e.g. inner halo virialization, vertical disc ‘settling’), and observations.

Copyright and License

© 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model.

Acknowledgement

We thank Alyson Brooks, Vadim Semenov, and Charlie Conroy for helpful conversations during the development of this draft. Support for PFH was provided by NSF Research Grants 1911233 & 20009234, NSF CAREER grant 1455342, NASA grants 80NSSC18K0562, HST-AR-15800.001-A. Numerical calculations were run on the Caltech compute cluster ‘Wheeler,’ allocations FTA-Hopkins supported by the NSF and TACC, and NASA HEC SMD-16-7592. MBK acknowledges support from NSF CAREER award AST-1752913, NSF grants AST-1910346 and AST-2108962, NASA grant 80NSSC22K0827, and HST-AR-15809, HST-GO-15658, HST-GO-15901, HST-GO-15902, HST-AR-16159, and HST-GO-16226 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. JS was supported by the Israel Science Foundation (grant No. 2584/21). CAFG was supported by NSF through grants AST-1715216, AST-2108230, and CAREER award AST-1652522; by NASA through grants 17-ATP17-0067 and 21-ATP21-0036; by STScI through grants HST-AR-16124.001-A and HST-GO-16730.016-A; by CXO through grant TM2-23005X; and by the Research Corporation for Science Advancement through a Cottrell Scholar Award. ZH was supported by a Gary A. McCue postdoctoral fellowship at UC Irvine. The Flatiron Institute is supported by the Simons Foundation. This work made use of the FIRE data repository hosted by the Flatiron Institute.

Data Availability

The data supporting this article are available on reasonable request to the corresponding author.

Additional details

Related works

Is new version of
Discussion Paper: arXiv:2301.08263 (arXiv)

Funding

National Science Foundation
AST-1911233
National Science Foundation
AST-20009234
National Science Foundation
AST-1455342
National Aeronautics and Space Administration
80NSSC18K0562
National Aeronautics and Space Administration
HST-AR-15800.001-A
National Aeronautics and Space Administration
SMD-16-7592
National Science Foundation
AST-1752913
National Science Foundation
AST-1910346
National Science Foundation
AST-2108962
National Aeronautics and Space Administration
80NSSC22K0827
National Aeronautics and Space Administration
HST-AR-15809
National Aeronautics and Space Administration
HST-GO-15658
National Aeronautics and Space Administration
HST-GO-15901
National Aeronautics and Space Administration
HST-GO-15902
National Aeronautics and Space Administration
HST-AR-16159
National Aeronautics and Space Administration
HST-GO-16226
National Aeronautics and Space Administration
NAS5-26555
Israel Science Foundation
2584/21
National Science Foundation
AST-1715216
National Science Foundation
AST-2108230
National Science Foundation
AST-1652522
National Aeronautics and Space Administration
17-ATP17-0067
National Aeronautics and Space Administration
21-ATP21-0036
National Aeronautics and Space Administration
HST-AR-16124.001-A
National Aeronautics and Space Administration
HST-GO-16730.016-A
National Aeronautics and Space Administration
TM2-23005X
Cottrell Scholar of Research Corporation
University of California, Irvine
Simons Foundation

Dates

Accepted
2023-06-20
Available
2023-06-24
Available
2023-08-28
Corrected and typeset

Caltech Custom Metadata

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