The confinement of star-forming galaxies into a main sequence through episodes of gas compaction, depletion and replenishment
By S. Tacchella, A. Dekel, C. Carollo, D. Ceverino, Colin Degraf, S. Lapiner, Nir Mandelker, Joel R. Primack. 2015
234 citations recorded by the source corpus.
Using cosmological simulations, we address the properties of high-redshift star-forming galaxies (SFGs) across their main sequence (MS) in the plane of star-formation rate (SFR) versus stellar mass. We relate them to the evolution of galaxies through phases of gas compaction, depletion, possible replenishment, and eventual quenching. We find that the high-SFR galaxies in the upper envelope of the MS are compact, with high gas fractions and short depletion times ("blue nuggets"), while the lower-SFR galaxies in the lower envelope have lower central gas densities, lower gas fractions and longer depletion times, consistent with observed gradients across the MS. Stellar-structure gradients are negligible. The SFGs oscillate about the MS ridge on timescales $\sim0.4~t_{\mathrm{Hubble}}$ ($\sim1$ Gyr at $z\sim3$). The propagation upwards is due to gas compaction, triggered, e.g., by mergers, counter-rotating streams, and/or violent disc instabilities. The downturn at the upper envelope is due to central gas depletion by peak star formation and outflows while inflow from the shrunken gas disc is suppressed. An upturn at the lower envelope can occur once the extended disc has been replenished by fresh gas and a new compaction can be triggered, namely as long as the replenishment time is shorter than the depletion time. The mechanisms of gas compaction, depletion and replenishment confine the SFGs to the narrow ($\pm0.3$ dex) MS. Full quenching occurs in massive haloes ($M_{\mathrm{vir}}>10^{11.5}~M_\odot$) and/or at low redshifts ($z<3$), where the replenishment time is long compared to the depletion time, explaining the observed bending down of the MS at the massive end.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/b76e4dcf5be37fb147e1e69eaae1aa8579d9e0b9
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In Astronomy and Astrophysics
Citations in the corpus
- Constraining the galaxy–halo connection over the last 13.3 Gyr: star formation histories, galaxy mergers and structural properties (2017, result): “Similar conclusions were reached in previous studies that analyzed observations and hydro simulations of galaxy formation (Barro et al. 2015; Tacchella et al. 2016).”
- A Redshift-independent Efficiency Model: Star Formation and Stellar Masses in Dark Matter Halos at z ≳ 4 (2018, background): “…et al. 2007a,b), but are sustained for extended periods of time in a quasi-steady state of gas inflow, gas outflow, and gas consumption (Bouché et al. 2010; Daddi et al. 2010; Genzel et al. 2010; Tacconi et al. 2010; Davé et al. 2012; Dekel et al. 2013; Lilly et al. 2013; Tacchella et al. 2016).”
- simba: Cosmological simulations with black hole growth and feedback (2019, background): “The discrepancy could also represent a failing in physics, if for instance low-mass galaxies are preferentially quenched via some rapid mode such as merging, violent disk instability, or stripping that is simultaneously associated with compactification (e.g. Tacchella et al. 2016).”
- PHIBSS: Unified Scaling Relations of Gas Depletion Time and Molecular Gas Fractions (2017, background): “Simulations suggest that in parallel to the average growth along the MS, SFGs oscillate up and down in sSFR across the MS-band (±0.6 dex) on a ~1 Gyr time scale, owing to increased and decreased gas accretion rates, and to internal gas transport and ‘compaction’ events (Tacchella et al. 2016).”
- A unified model for galactic discs: star formation, turbulence driving, and mass transport (2017, background): “…∼0.1–0.3 virial radii, which is ∼10 times the stellar scale length (Danovich et al. 2015), though there are exceptions associated with loss of angular momentum by counter-rotating streams and major mergers, which tend to trigger ‘compaction’ events (Zolotov et al. 2015; Tacchella et al. 2016a,b).”