Equilibrium initialization and stability of three-dimensional gas discs

Wang, Hsiang-Hsu; Klessen, Ralf S.; Dullemond, C. P.; Bosch, Frank C. van den; Fuchs, B.

doi:10.1111/j.1365-2966.2010.16942.x

Cited by 49 publications

(74 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For thick discs, as is the case here, a similar criterion may be found that deviates only by a factor of of the order of unity (e.g. Wang et al 2010). For Q 1, the pressure of the gas and the shear by the differential rotation of the disc are sufficient to prevent local collapse, while for Q 1 the disc fulfils the Toomre criterion and becomes unstable, leading to the formation of spiral arms that transport mass inwards and angular momentum outwards.…”

Section: Disc Formation and Fragmentationsupporting

confidence: 77%

Formation and evolution of primordial protostellar systems

Greif

Clark

Glover

et al. 2012

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

We investigate the formation of the first stars at the end of the cosmic dark ages with a suite of three-dimensional, moving mesh simulations that directly resolve the collapse of the gas beyond the formation of the first protostar at the centre of a dark matter minihalo. The simulations cover more than 25 orders of magnitude in density and have a maximum spatial resolution of 0.05 R ⊙ , which extends well below the radius of individual protostars and captures their interaction with the surrounding gas. In analogy to previous studies that employed sink particles, we find that the Keplerian disc around the primary protostar fragments into a number of secondary protostars, which is facilitated by H 2 collisional dissociation cooling and collision-induced emission. The further evolution of the protostellar system is characterized by strong gravitational torques that transfer angular momentum between the secondary protostars formed in the disc and the surrounding gas. This leads to the migration of about half of the secondary protostars to the centre of the cloud in a free-fall time, where they merge with the primary protostar and enhance its growth to about five times the mass of the second most massive protostar. By the same token, a fraction of the protostars obtain angular momentum from other protostars via N-body interactions and migrate to higher orbits. On average, only every third protostar survives until the end of the simulation. However, the number of protostars present at any given time increases monotonically, suggesting that the system will continue to grow beyond the limited period of time simulated here.

show abstract

Section: Disc Formation and Fragmentationsupporting

confidence: 77%

Formation and evolution of primordial protostellar systems

Greif

Clark

Glover

et al. 2012

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

show abstract

“…The Q parameter was originally proposed to determine whether perturbations can grow in an infinitely thin, isothermal disc. Later studies have extended this criterion for thick discs, finding that it only deviates by a factor of order unity from the above equation (Wang et al 2010). For Figure 7.…”

Section: Disc Formation and Fragmentationmentioning

confidence: 93%

Formation of massive protostars in atomic cooling haloes

Becerra

Greif

Springel

et al. 2014

Monthly Notices of the Royal Astronomical Society

134

View full text Add to dashboard Cite

We present the highest-resolution three-dimensional simulation to date of the collapse of an atomic cooling halo in the early Universe. We use the moving-mesh code arepo with the primordial chemistry module introduced in Greif (2014), which evolves the chemical and thermal rate equations for over more than 20 orders of magnitude in density. Molecular hydrogen cooling is suppressed by a strong Lyman-Werner background, which facilitates the near-isothermal collapse of the gas at a temperature of about 10 4 K. Once the central gas cloud becomes optically thick to continuum emission, it settles into a Keplerian disc around the primary protostar. The initial mass of the protostar is about 0.1 M , which is an order of magnitude higher than in minihaloes that cool via molecular hydrogen. The high accretion rate and efficient cooling of the gas catalyse the fragmentation of the disc into a small protostellar system with 5 − 10 members. After about 12 yr, strong gravitational interactions disrupt the disc and temporarily eject the primary protostar from the centre of the cloud. By the end of the simulation, a secondary clump has collapsed at a distance of 150 au from the primary clump. If this clump undergoes a similar evolution as the first, the central gas cloud may evolve into a wide binary system. High accretion rates of both the primary and secondary clumps suggest that fragmentation is not a significant barrier for forming at least one massive black hole seed.

show abstract

“…For example, a non-negligible thickness of a disc naturally weakens the gravitational forces within the disc plane, and thus lowers the value of Qcrit for instability (e.g. Goldreich & Lynden-Bell 1965;Romeo 1992Romeo , 1994Wang et al 2010;Behrendt et al 2015). Alternatively, one can compute an approximated thickness-corrected Q parameter keeping the stability criterion at unity as Q thick = T Q, where…”

Section: Deviations From the Fiducial Q Valuesmentioning

confidence: 99%

Non-linear violent disc instability with high Toomre'sQin high-redshift clumpy disc galaxies

Inoue¹,

Dekel²,

Mandelker³

et al. 2015

Mon. Not. R. Astron. Soc.

115

102

View full text Add to dashboard Cite

We utilize zoom-in cosmological simulations to study the nature of violent disc instability (VDI) in clumpy galaxies at high redshift, z = 1-5. Our simulated galaxies are not in the ideal state assumed in Toomre instability, of linear fluctuations in an isolated, uniform, rotating disk. There, instability is characterised by a Q parameter below unity, and lower when the disk is thick. Instead, the high-redshift discs are highly perturbed. Over long periods they consist of non-linear perturbations, compact massive clumps and extended structures, with new clumps forming in inter-clump regions. This is while the galaxy is subject to frequent external perturbances. We compute the local, two-component Q parameter for gas and stars, smoothed on a ∼ 1 kpc scale to capture clumps of 10 8−9 M ⊙ . The Q < 1 regions are confined to collapsed clumps due to the high surface density there, while the inter-clump regions show Q significantly higher than unity. Tracing the clumps back to their relatively smooth Lagrangian patches, we find that Q prior to clump formation typically ranges from unity to a few. This is unlike the expectations from standard Toomre instability. We discuss possible mechanisms for high-Q clump formation, e.g. rapid turbulence decay leading to small clumps that grow by mergers, non-axisymmetric instability, or clump formation induced by non-linear perturbations in the disk. Alternatively, the high-Q non-linear VDI may be stimulated by the external perturbations such as mergers and counter-rotating streams. The high Q may represent excessive compressive modes of turbulence, possibly induced by tidal interactions.

show abstract

Equilibrium initialization and stability of three-dimensional gas discs

Cited by 49 publications

References 52 publications

Formation and evolution of primordial protostellar systems

Formation and evolution of primordial protostellar systems

Formation of massive protostars in atomic cooling haloes

Non-linear violent disc instability with high Toomre'sQin high-redshift clumpy disc galaxies

Contact Info

Product

Resources

About