The link between the assembly of the inner dark matter halo and the angular momentum evolution of galaxies in the EAGLE simulation

Zavala, Jesús; Frenk, Carlos S.; Bower, Richard G.; Schaye, Joop; Theuns, Tom; Crain, Robert A.; Trayford, James W.; Schaller, Matthieu; Furlong, Michelle

doi:10.1093/mnras/stw1286

Cited by 109 publications

(139 citation statements)

References 71 publications

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“…This parameter is usually defined as = jz/j(E), where j(E) is the maximum specific angular momentum possible for a star with specific binding energy E (Abadi et al 2003), or as V = jz/rvc(r), where vc(r) = GM (< r)/r is the circular velocity at the distance r (Scannapieco et al 2009(Scannapieco et al , 2012. Some examples of such circularity-based morphological parameters include the discto-total ratio, defined as the fraction of stars with sufficiently circular orbits, typically D/T = f ( > 0.7) ≈ f ( V > 0.8) (Aumer et al 2013;Marinacci, Pakmor & Springel 2014), or the bulge-tototal fraction, usually defined as B/T = 2 × f ( < 0) (but see Martig et al 2012;Zavala et al 2016, for an improved B/T measurement). We have found that κrot is strongly correlated with any of these alternative measures of kinematic morphology, despite the fact that κrot cannot distinguish the sense of rotation of a particle about the z-axis, i.e.…”

Section: The Amount Of Rotational Supportmentioning

confidence: 99%

“…Instead, Sales et al (2012) proposed that a disc forms when the angular momentum of freshly accreted gas is aligned with that of earlier gas accretion. Furthermore, Zavala et al (2016) found that galaxy morphology is correlated with the assembly history of the inner DM halo. In particular, they found that the 'angular momentum loss' of a galaxy's stellar component is strongly linked to that of the inner DM halo, whereas the angular momentum history of a galaxy's cold gas is statistically correlated with that of the whole DM halo.…”

Section: Introductionmentioning

confidence: 99%

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The role of mergers and halo spin in shaping galaxy morphology

Rodríguez-Gómez

Sales

Genel

et al. 2017

Monthly Notices of the Royal Astronomical Society

190

157

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Mergers and the spin of the dark matter halo are factors traditionally believed to determine the morphology of galaxies within a ΛCDM cosmology. We study this hypothesis by considering approximately 18,000 central galaxies at z = 0 with stellar masses M * = 10 9 -10 12 M selected from the Illustris cosmological hydrodynamic simulation. The fraction of accreted stars -which measures the importance of massive, recent and dry mergers -increases steeply with galaxy stellar mass, from less than 5 per cent in dwarfs to 80 per cent in the most massive objects, and the impact of mergers on galaxy morphology increases accordingly. For galaxies with M * 10 11 M , mergers have the expected effect: if gas-poor they promote the formation of spheroidal galaxies, whereas gas-rich mergers favour the formation and survivability of massive discs. This trend, however, breaks at lower masses. For objects with M * 10 11 M , mergers do not seem to play any significant role in determining the morphology, with accreted stellar fractions and mean merger gas fractions that are indistinguishable between spheroidal and disc-dominated galaxies. On the other hand, halo spin correlates with morphology primarily in the least massive objects in the sample (M * 10 10 M ), but only weakly for galaxies above that mass. Our results support a scenario where (1) mergers play a dominant role in shaping the morphology of massive galaxies, (2) halo spin is important for the morphology of dwarfs, and (3) the morphology of medium-sized galaxies -including the Milky Way -shows little dependence on galaxy assembly history or halo spin, at least when these two factors are considered individually.

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Section: The Amount Of Rotational Supportmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of mergers and halo spin in shaping galaxy morphology

Rodríguez-Gómez

Sales

Genel

et al. 2017

Monthly Notices of the Royal Astronomical Society

190

157

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“…Sales et al (2009) and Stevens et al (2016) showed that the MMW model fails to match the output of the EAGLE simulation and its ancestor OWLS. Zavala et al (2016) found the angular momentum of stars to correlate with that of the inner halo in EAGLE, and Sales et al (2012) reported weak correlation of galaxy properties with halo spin in the related GIMIC simulation. This is in contrast with other simulations in which halo spin correlates more strongly with galaxy spin and morphology, especially at low mass (e.g.…”

Section: Introductionmentioning

confidence: 99%

On the galaxy–halo connection in the EAGLE simulation

Desmond

Mao

Crain

et al. 2017

Monthly Notices of the Royal Astronomical Society: Letters

Self Cite

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Empirical models of galaxy formation require assumptions about the correlations between galaxy and halo properties. These may be calibrated against observations or inferred from physical models such as hydrodynamical simulations. In this Letter, we use the EAGLE simulation to investigate the correlation of galaxy size with halo properties. We motivate this analysis by noting that the common assumption of angular momentum partition between baryons and dark matter in rotationally supported galaxies overpredicts both the spread in the stellar mass-size relation and the anticorrelation of size and velocity residuals, indicating a problem with the galaxy-halo connection it implies. We find the EAGLE galaxy population to perform significantly better on both statistics, and trace this success to the weakness of the correlations of galaxy size with halo mass, concentration and spin at fixed stellar mass. Using these correlations in empirical models will enable fine-grained aspects of galaxy scalings to be matched.

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“…Teklu et al 2015). In particular, they are able to reproduce the parallel scaling relations of angular momentum versus stellar mass displayed by observed early-type and latetype galaxies (Zavala et al 2016). These advances open the door to detailed studies that will elucidate the nature of angular momentum evolution in a fully (hydro)dynamical cosmological context (e.g.…”

Section: Introductionmentioning

confidence: 89%

“…Second, it employs a Lagrangian analysis in a simulation based on a mesh code, using tracer particles, while previous Lagrangian analyses on this topic have all been based on Smoothed Particle Hydrodynamics (SPH) (e.g. Zavala et al 2016). …”

Section: Introductionmentioning

confidence: 99%

The Impact of Galactic Winds on the Angular Momentum of Disk Galaxies in the Illustris Simulation

DeFelippis

Genel

Bryan

et al. 2017

ApJ

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Observed galactic disks have specific angular momenta similar to expectations for typical dark matter halos in ΛCDM. Cosmological hydrodynamical simulations have recently reproduced this similarity in large galaxy samples by including strong galactic winds, but the exact mechanism that achieves this is not yet clear. Here we present an analysis of key aspects contributing to this relation: angular momentum selection and evolution of Lagrangian mass elements as they accrete onto dark matter halos, condense into Milky Way-scale galaxies, and join the z = 0 stellar phase. We contrast this evolution in the Illustris simulation with that in a simulation without galactic winds, where the z = 0 angular momentum is ≈ 0.6 dex lower. We find that winds induce differences between these simulations in several ways: increasing angular momentum, preventing angular momentum loss, and causing z = 0 stars to sample the accretion-time angular momentum distribution of baryons in a biased way. In both simulations, gas loses on average ≈ 0.4 dex between accreting onto halos and first accreting onto central galaxies. In Illustris, this is followed by ≈ 0.2 dex gains in the 'galactic wind fountain' and no further net evolution past the final accretion onto the galaxy. Without feedback, further losses of ≈ 0.2 dex occur in the gas phase inside the galaxies. An additional ≈ 0.15 dex difference arises from feedback preferentially selecting higher angular momentum gas at accretion by expelling gas that is poorly aligned. These and additional effects of similar magnitude are discussed, suggesting a complex origin of the similarity between the specific angular momenta of galactic disks and typical halos.

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The link between the assembly of the inner dark matter halo and the angular momentum evolution of galaxies in the EAGLE simulation

Cited by 109 publications

References 71 publications

The role of mergers and halo spin in shaping galaxy morphology

The role of mergers and halo spin in shaping galaxy morphology

On the galaxy–halo connection in the EAGLE simulation

The Impact of Galactic Winds on the Angular Momentum of Disk Galaxies in the Illustris Simulation

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