High-redshift clumpy discs and bulges in cosmological simulations

By D. Ceverino, A. Dekel, Frédéric Bournaud. 2009

411 citations recorded by the source corpus.

We analyse the first cosmological simulations that recover the fragmentation of high-redshift galactic discs driven by cold streams. The fragmentation is recovered owing to an AMR resolution better than 70 pc with cooling below 104 K. We study three typical star-forming galaxies in haloes of ∼5 × 1011 M⊙ at z≃ 2.3 when they were not undergoing a major merger. The steady gas supply by cold streams leads to gravitationally unstable, turbulent discs, which fragment into giant clumps and transient features on a dynamical time-scale. The disc clumps are not associated with dark-matter haloes. The clumpy discs are self-regulated by gravity in a marginally unstable state. Clump migration and angular-momentum transfer on an orbital time-scale help the growth of a central bulge with a mass comparable to the disc. The continuous gas input keeps the system of clumpy disc and bulge in a near steady state for several Gyr. The average star formation rate, much of which occurs in the clumps, follows the gas accretion rate of ∼45 M⊙ yr−1. The simulated galaxies resemble in many ways the observed star-forming galaxies at high redshift. Their properties are consistent with the simple theoretical framework presented in Dekel, Sari & Ceverino. In particular, a two-component analysis reveals that the simulated discs are indeed marginally unstable, and the time evolution confirms the robustness of the clumpy configuration in a cosmological steady state. By z∼ 1, the simulated systems are stabilized by a dominant stellar spheroid, demonstrating the process of ‘morphological quenching’ of star formation. We demonstrate that the disc fragmentation is not a numerical artefact once the Jeans length is kept larger than nearly seven resolution elements, i.e. beyond the standard Truelove criterion.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/307ed0ed1e683023647fd676fb4bc0437d99ec35

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. R. Dav'e
4. R. Somerville
5. A. Dekel
6. Volker Springel
7. T. Naab
8. C. Conroy

In Instrumentation

1. P. Hopkins
2. L. Hernquist
3. A. Dekel
4. R. Dav'e
5. R. Somerville
6. P. V. van Dokkum
7. Christopher J. Conselice
8. C. Conroy

Citations in the corpus

• Structural and Star-forming Relations since z ∼ 3: Connecting Compact Star-forming and Quiescent Galaxies (2015, background): “…with dissipational processes ranging from major mergers (Hopkins et al. 2006; Hopkins et al. 2008), to violent gravitational instabilities (Dekel et al. 2009a; Dekel & Burkert 2014; Ceverino et al. 2010), and weaker secular instabilities (e.g., bars and spiral arms; Kormendy & Kennicutt 2004).”
• EVIDENCE FOR WIDE-SPREAD ACTIVE GALACTIC NUCLEUS-DRIVEN OUTFLOWS IN THE MOST MASSIVE z ∼ 1–2 STAR-FORMING GALAXIES (2014, background): “…disk to the center, as advocated by many theoretical studies (Noguchi 1999; Immeli et al. 2004a, 2004b; Genzel et al. 2008; Bournaud et al. 2009; Ceverino et al. 2010; Dekel & Burkert T h e A stroph ysical Jou rn al,796:7 (25pp),2014 N ovem ber 20 G en zel et al. Table 4 Outflow…”
• Evolution of density profiles in high-z galaxies: compaction and quenching inside-out (2015, methodology): “Supernovae and stellar winds are implemented by local injection of thermal energy as in Ceverino & Klypin (2009); Ceverino et al. (2010) and Ceverino et al. (2012).”
• THE RELATION BETWEEN STAR FORMATION RATE AND STELLAR MASS FOR GALAXIES AT 3.5 ⩽ z ⩽ 6.5 IN CANDELS (2014, background): “…are subdominant to galaxy growth at high redshift z > 2 (Murali et al. 2002; Kereš et al. 2005) and the SFR tracks the gas accretion rate (Birnboim & Dekel 2003; Katz et al. 2003; Kereš et al. 2005; Dekel et al. 2009; Bouché et al. 2010; Ceverino et al. 2010; FaucherGiguère et al. 2011).”
• Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies (2014, background): “(vii) Cosmological zoom-in simulations of the cosmic web (e.g. Ocvirk et al. 2008; Ceverino et al. 2010) from which the cold accretion scenario of galaxy mass assembly has been implied Dekel et al. (2009) show that clumpy substructures develop within the gas filaments.”
• A general model for the CO–H2 conversion factor in galaxies with applications to the star formation law (2011, background): “…unstable even in the model disc galaxies at z ∼ 2, similar to both observations (e.g. Elmegreen, Bournaud & Elmegreen 2008; Elmegreen et al. 2009a,b; Genzel et al. 2011), and recent simulations with other codes (e.g. Bournaud et al. 2008, 2010, 2011; Dekel et al. 2009; Ceverino et al. 2010).”
• REGULARITY UNDERLYING COMPLEXITY: A REDSHIFT-INDEPENDENT DESCRIPTION OF THE CONTINUOUS VARIATION OF GALAXY-SCALE MOLECULAR GAS PROPERTIES IN THE MASS-STAR FORMATION RATE PLANE (2013, positive): “Since clumps are a telltale signature of violent disk instabilities in gas-rich high-redshift galaxies (e.g., Agertz et al. 2009, Ceverino et al. 2010, Förster Schreiber et al. 2011, Swinbank et al. 2011, Wuyts et al. 2012) this observation thus provides independent evidence for increasing gas…”
• THE SINS SURVEY OF z ∼ 2 GALAXY KINEMATICS: PROPERTIES OF THE GIANT STAR-FORMING CLUMPS (2010, methodology): “…10tdyn(Rdisk) < 0.5 Gyr, (1) where they may form a central bulge and a remnant thick disk (Noguchi 1999; Immeli et al. 2004a, 2004b; Förster Schreiber et al. 2006; Genzel et al. 2006, 2008; Elmegreen et al. 2008; Carollo et al. 2007; Dekel et al. 2009a; Bournaud et al. 2009; Ceverino et al. 2010).”
• ON THE ORIGIN OF THE EXTENDED Hα FILAMENTS IN COOLING FLOW CLUSTERS (2010, background): “Figure 3 from Ceverino et al. (2010) shows long (>50 kpc), thin (<10 kpc) filaments of cold gas which resemble our observations of Hα filaments.”
• THE EPOCH OF DISK SETTLING: z ∼ 1 TO NOW (2012, background): “2009; Ceverino et al. 2010; Brook et al. 2011; Kimm et al. 2011; Martig et al. 2012, and references therein).”
• Four phases of angular-momentum buildup in high-z galaxies: from cosmic-web streams through an extended ring to disc and bulge (2014, background): “…highly perturbed, with large transient features and in situ giant clumps (Noguchi 1999; Immeli et al. 2004; Genzel et al. 2006; Bournaud, Elmegreen & Elmegreen 2007; Genzel et al. 2008; Agertz, Teyssier & Moore 2009; Dekel, Sari & Ceverino 2009; Ceverino et al. 2010, 2012; Mandelker et al. 2014).”
• THE DEPENDENCE OF QUENCHING UPON THE INNER STRUCTURE OF GALAXIES AT 0.5 ⩽ z < 0.8 IN THE DEEP2/AEGIS SURVEY (2012, background): “A recent analysis of a set of three high-resolution AMR simulations atz≃ 2.3 by Ceverino et al. (2010) demonstrates this process.”
• Radiative feedback and the low efficiency of galaxy formation in low-mass haloes at high redshift (2013, methodology): “Artificial fragmentation on the cell size is prevented by introducing a pressure floor, which ensures that the Jeans scale is resolved by at least 7 cells (Ceverino et al. 2010).”
• SHORT-LIVED STAR-FORMING GIANT CLUMPS IN COSMOLOGICAL SIMULATIONS OF z ≈ 2 DISKS (2010, background): “For example, the three clumpy disks simulated by Ceverino et al. (2010) in a cosmological context with less effective feedback have gas fractions as low as 18%,14%,4% and baryon conversion efficiencies as high as 0.26,0.22,1.14, both indicating too little suppression of starformation when compared…”