BREATHING FIRE: HOW STELLAR FEEDBACK DRIVES RADIAL MIGRATION, RAPID SIZE FLUCTUATIONS, AND POPULATION GRADIENTS IN LOW-MASS GALAXIES

By K. El-Badry, Andrew Wetzel, M. Geha, P. Hopkins, D. Keres̆, Tsang Keung Chan, C. Faucher-Giguére. 2015

152 citations recorded by the source corpus.

We examine the effects of stellar feedback and bursty star formation on low-mass galaxies (Mstar = 2 × 106 − 5 × 1010 M⊙) using the Feedback in Realistic Environments (FIRE) simulations. While previous studies emphasized the impact of feedback on dark matter profiles, we investigate the impact on the stellar component: kinematics, radial migration, size evolution, and population gradients. Feedback-driven outflows/inflows drive significant radial stellar migration over both short and long timescales via two processes: (1) outflowing/infalling gas can remain star-forming, producing young stars that migrate ∼1 kpc within their first 100 Myr, and (2) gas outflows/inflows drive strong fluctuations in the global potential, transferring energy to all stars. These processes produce several dramatic effects. First, galaxies’ effective radii can fluctuate by factors of >2 over ∼200 Myr, and these rapid size fluctuations can account for much of the observed scatter in the radius at fixed Mstar. Second, the cumulative effects of many outflow/infall episodes steadily heat stellar orbits, causing old stars to migrate outward most strongly. This age-dependent radial migration mixes—and even inverts—intrinsic age and metallicity gradients. Thus, the galactic-archaeology approach of calculating radial star formation histories from stellar populations at z = 0 can be severely biased. These effects are strongest at Mstar ≈ 107–9.6 M⊙, the same regime where feedback most efficiently cores galaxies. Thus, detailed measurements of stellar kinematics in low-mass galaxies can strongly constrain feedback models and test baryonic solutions to small-scale problems in ΛCDM.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/0e0988b703f43e518f0be58eef60496ff0a9f0a7

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Citations in the corpus

FIRE in the field: Simulating the threshold of galaxy formation (2016, background): “…including realistic galactic outflows (Muratov et al. 2015), the mass-metallicity relation (Ma et al. 2016), the mass-size relation and age/metallicity gradients (El-Badry et al. 2016), cored dark-matter profiles (Oñorbe et al. 2015; Chan et al. 2015), and stellar kinematics (Wheeler et al. 2015b).”
FIRE-2 simulations: physics versus numerics in galaxy formation (2017, background): “…and cusp/core structure of dwarfs (Oñorbe et al. 2015; Chan et al. 2015; Wheeler et al. 2015, 2017; Wetzel et al. 2016); abundance gradients (El-Badry et al. 2016; Ma et al. 2017a); neutral hydrogen absorption in the CGM (Faucher-Giguere et al. 2015; Faucher-Giguère et al. 2016; Hafen…”
The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, background): “Powerful bursty gaseous outflows have been shown to be able to ‘drag’ many of the constituent stars to much larger radii overall, thus creating noticeably diffuse dwarf galaxies (see e.g. El-Badry et al. 2016; Di Cintio et al. 2017; Chan et al. 2018).”
Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies (2017, background): “-size relation (El-Badry et al. 2016), the HI content of galaxy halos at both low and high redshift (Faucher-Giguère et al. 2015, 2016; Hafen et al. 2016), and the structure and star formation histories of isolated dwarf galaxies (Oñorbe et al. 2015; Chan et al. 2015; Fitts et al. 2016).”
RECONCILING DWARF GALAXIES WITH ΛCDM COSMOLOGY: SIMULATING A REALISTIC POPULATION OF SATELLITES AROUND A MILKY WAY–MASS GALAXY (2016, background): “…several key observables: realistic galactic outflows (Muratov et al. 2015), Mstarmetallicity relation (Ma et al. 2016), Mstar-size relation (El-Badry et al. 2016), cored dark-matter profiles (Oñorbe et al. 2015; Chan et al. 2015), and dispersiondominated stellar kinematics (Wheeler et al.…”
The structure and dynamical evolution of the stellar disc of a simulated Milky Way-mass galaxy (2016, methodology): “We pick this simulation because it has been well-studied in previous work (e.g. Hopkins et al. 2014; Muratov et al. 2015, 2016; El-Badry et al. 2016) and has a morphology that is closest to the MW in our suite.”
The Local Group on FIRE: dwarf galaxy populations across a suite of hydrodynamic simulations (2018, background): “…1 kpc. galaxies are at the centres of haloes that reached ∼1010.5 M (Garrison-Kimmel et al. 2014a), previous work has shown that mass scale to be the most susceptible to core formation and stellar migration due to supernovae feedback (Di Cintio et al. 2014b; Chan et al. 2015; El-Badry et al. 2016).”
Black holes on FIRE: stellar feedback limits early feeding of galactic nuclei (2017, background): “In such galaxies, inefficient BH growth may correlate with the formation of dark matter cores and stellar size fluctuations driven by stellar feedback (e.g. Chan et al. 2015; El-Badry et al. 2016).”