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Turbulent Gas-rich Disks at High Redshift : Origin of Thick Stellar Disks Through 3D “Baryon Sloshing”

Bland-Hawthorn, Joss LU ; Tepper-Garcia, Thor ; Agertz, Oscar LU ; Federrath, Christoph ; Haywood, Misha ; di Matteo, Paola ; Bedding, Timothy R. ; Tsukui, Takafumi ; Wisnioski, Emily and Ness, Melissa , et al. (2025) In Astrophysical Journal 994(1).
Abstract

In response to recent observations from JWST and Atacama Large Millimeter Array, we explore a new class of dynamically self-consistent models that mimics a plausible progenitor of the Milky Way over a wide range of disk gas fractions, fgas. The high gas surface densities encourage vigorous star formation, which in turn couples with the gas to drive turbulence. We show that this coupling through momentum recoil drives a random walk of the baryonic potential minimum with respect to total gravitational potential, Φtot(R, f, z). The amplitude of the bulk motion depends on the feedback strength, which in turn is directly associated with fgas. At its most extreme, when gas is the sole contributor to the disk... (More)

In response to recent observations from JWST and Atacama Large Millimeter Array, we explore a new class of dynamically self-consistent models that mimics a plausible progenitor of the Milky Way over a wide range of disk gas fractions, fgas. The high gas surface densities encourage vigorous star formation, which in turn couples with the gas to drive turbulence. We show that this coupling through momentum recoil drives a random walk of the baryonic potential minimum with respect to total gravitational potential, Φtot(R, f, z). The amplitude of the bulk motion depends on the feedback strength, which in turn is directly associated with fgas. At its most extreme, when gas is the sole contributor to the disk potential (fgas = 100%), the amplitude of the walk can reach up to R ≈ 5 kpc within Φtot. The disk dominates over dark matter (fdisk ≳ 50%) within Rs = 2.2Rdisk, where Rdisk is the exponential disk scale length. For a lower fdisk and/or fgas, the 3D sloshing amplitude and velocity are reduced. The combination of strong feedback and sloshing leads to the newly formed stars being dynamically heated and settling to a more spatially extended disk population. The 3D heating process is roughly isotropic but its effects are more noticeable in |z| due to the initial dynamical coldness of the star-forming disk. Such a disk has enhanced [α/Fe] stellar abundances and a vertical (but no radial) gradient in stellar age and metallicity, both consistent with the Milky Way’s thick stellar disk.

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Contribution to journal
publication status
published
subject
in
Astrophysical Journal
volume
994
issue
1
article number
22
publisher
American Astronomical Society
external identifiers
  • scopus:105034318162
ISSN
0004-637X
DOI
10.3847/1538-4357/ae0931
language
English
LU publication?
yes
id
2b09eeeb-8c4f-48d0-9f93-4266bff8ff55
date added to LUP
2026-06-08 15:45:40
date last changed
2026-06-08 15:46:52
@article{2b09eeeb-8c4f-48d0-9f93-4266bff8ff55,
  abstract     = {{<p>In response to recent observations from JWST and Atacama Large Millimeter Array, we explore a new class of dynamically self-consistent models that mimics a plausible progenitor of the Milky Way over a wide range of disk gas fractions, f<sub>gas</sub>. The high gas surface densities encourage vigorous star formation, which in turn couples with the gas to drive turbulence. We show that this coupling through momentum recoil drives a random walk of the baryonic potential minimum with respect to total gravitational potential, Φ<sub>tot</sub>(R, f, z). The amplitude of the bulk motion depends on the feedback strength, which in turn is directly associated with f<sub>gas</sub>. At its most extreme, when gas is the sole contributor to the disk potential (f<sub>gas</sub> = 100%), the amplitude of the walk can reach up to R ≈ 5 kpc within Φ<sub>tot</sub>. The disk dominates over dark matter (f<sub>disk</sub> ≳ 50%) within R<sub>s</sub> = 2.2R<sub>disk</sub>, where R<sub>disk</sub> is the exponential disk scale length. For a lower f<sub>disk</sub> and/or f<sub>gas</sub>, the 3D sloshing amplitude and velocity are reduced. The combination of strong feedback and sloshing leads to the newly formed stars being dynamically heated and settling to a more spatially extended disk population. The 3D heating process is roughly isotropic but its effects are more noticeable in |z| due to the initial dynamical coldness of the star-forming disk. Such a disk has enhanced [α/Fe] stellar abundances and a vertical (but no radial) gradient in stellar age and metallicity, both consistent with the Milky Way’s thick stellar disk.</p>}},
  author       = {{Bland-Hawthorn, Joss and Tepper-Garcia, Thor and Agertz, Oscar and Federrath, Christoph and Haywood, Misha and di Matteo, Paola and Bedding, Timothy R. and Tsukui, Takafumi and Wisnioski, Emily and Ness, Melissa and Freeman, Ken}},
  issn         = {{0004-637X}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{1}},
  publisher    = {{American Astronomical Society}},
  series       = {{Astrophysical Journal}},
  title        = {{Turbulent Gas-rich Disks at High Redshift : Origin of Thick Stellar Disks Through 3D “Baryon Sloshing”}},
  url          = {{http://dx.doi.org/10.3847/1538-4357/ae0931}},
  doi          = {{10.3847/1538-4357/ae0931}},
  volume       = {{994}},
  year         = {{2025}},
}