Compaction and quenching of high-z galaxies in cosmological simulations: blue and red nuggets

By A. Zolotov, A. Dekel, Nir Mandelker, Dylan Tweed, Shigeki Inoue, Colin Degraf, D. Ceverino, Joel R. Primack, G. Barro, S. Faber. 2014

395 citations recorded by the source corpus.

We use cosmological simulations to study a characteristic evolution pattern of high redshift galaxies. Early, stream-fed, highly perturbed, gas-rich discs undergo phases of dissipative contraction into compact, star-forming systems (blue nuggets) at z~4-2. The peak of gas compaction marks the onset of central gas depletion and inside-out quenching into compact ellipticals (red nuggets) by z~2. These are sometimes surrounded by gas rings or grow extended dry stellar envelopes. The compaction occurs at a roughly constant specific star-formation rate (SFR), and the quenching occurs at a constant stellar surface density within the inner kpc ($\Sigma_1$). Massive galaxies quench earlier, faster, and at a higher $\Sigma_1$ than lower-mass galaxies, which compactify and attempt to quench more than once. This evolution pattern is consistent with the way galaxies populate the SFR-radius-mass space, and with gradients and scatter across the main sequence. The compaction is triggered by an intense inflow episode, involving (mostly minor) mergers, counter-rotating streams or recycled gas, and is commonly associated with violent disc instability. The contraction is dissipative, with the inflow rate >SFR, and the maximum $\Sigma_1$ anti-correlated with the initial spin parameter, as predicted by Dekel & Burkert (2014). The central quenching is triggered by the high SFR and stellar/supernova feedback (possibly also AGN feedback) due to the high central gas density, while the central inflow weakens as the disc vanishes. Suppression of fresh gas supply by a hot halo allows the long-term maintenance of quenching once above a threshold halo mass, inducing the quenching downsizing.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/43fab92f285e62bcaf4ecd104dd2114b873d8e63

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Citations in the corpus

MOSFIRE Spectroscopy of Quiescent Galaxies at 1.5 < z < 2.5. II. Star Formation Histories and Galaxy Quenching (2018, methodology): “Using a suite of hydrodynamical simulations, Zolotov et al. (2015) showed that mergers or violent disk instabilities can trigger a compaction event in which a massive stellar core is formed in a short time, with a resulting decrease in the galaxy effective size.”
Constraining the galaxy–halo connection over the last 13.3 Gyr: star formation histories, galaxy mergers and structural properties (2017, result): “Our findings, unfortunately, cannot be compared directly to the wet (gas inflow) compaction model (Dekel & Burkert 2014; Zolotov et al. 2015; Tacchella et al. 2016).”
Structural and Star-forming Relations since z ∼ 3: Connecting Compact Star-forming and Quiescent Galaxies (2015, methodology): “These galaxies quenched star-formation in the core, but continued to grow in stellar mass due to star-formation in a re-grown disk (Zolotov et al. 2015).”
Evolution of density profiles in high-z galaxies: compaction and quenching inside-out (2015, background): “…when the circumgalactic medium in the host halo becomes hot, typically when the halo mass is above the critical mass for virial shock heating, and at late times when cold streams do not penetrate efficiently (Birnboim & Dekel 2003; Kereš et al. 2005; Dekel & Birnboim 2006; Zolotov et al. 2015).”
A unified model for galactic discs: star formation, turbulence driving, and mass transport (2017, background): “…the range we consider, which tend to quench at z ∼ 2, both observations (Barro et al. 2013, 2016, 2017; Tacchella et al. 2015, 2018) and simulations (Zolotov et al. 2015; Tacchella et al. 2016a,b) suggest that galaxies pass through a phase of ‘compaction’, where the central gas surface density is…”
FORMING COMPACT MASSIVE GALAXIES (2015, methodology): “Thin black curves are individual simulated galaxies in Zolotov et al. (2015), fromz = 3 to z = 1.5.”
The confinement of star-forming galaxies into a main sequence through episodes of gas compaction, depletion and replenishment (2015, methodology): “Alternatively, if we replace the redshift cut by a cut in stellar surface density within the inner 1 kpc, ΣM?,1kpc < 10 9 M , as in Zolotov et al. (2015), we obtain a value of sb that is consistent within the uncertainty with the above value, which we adopt here.”
The size evolution of star-forming and quenched galaxies in the IllustrisTNG simulation (2017, methodology): “…involving major mergers, compact star-formation configurations triggered by either mergers or internal gravitational instabilities, and star-formation in extended disks, but may also reveal regularities and characteristics that can be categorized into a few main classes (e.g. Zolotov et al. 2015).”