Numerical Astrophysics: Galaxy Formation and Evolution

    General
    Description

    How galaxies formed and evolved through cosmic time is one of the key questions of modern astronomy and astrophysics. Cosmological time- and length-scales are so large that the evolution of individual galaxies cannot be directly observed. Only through numerical simulations can one follow the emergence of cosmic structures within the current cosmological paradigm.

    The main physical processes in galaxy formation and evolution are gravity, hydrodynamics, gas cooling, star formation, stellar evolution, supernova (SN) and black hole (BH) feedback. These are highly non-linear, thus difficult to describe with analytic models. Moreover, the presence of baryonic matter induces biases that collisionless (“dark matter”) simulations alone cannot reproduce (e.g. van Daalen et al. 2014, MNRAS, 440, 2997; Velliscig et al. 2014, MNRAS, 442, 2641). Semi-analytic models based on these simulations require ad hoc corrections to account for these biases. Hydrodynamic, cosmological simulations are therefore the preferred tool for conducting “controlled experiments” of galaxy formation and evolution.

    After three decades of advances in numerical simulations, theorists have only recently been able to reproduce simultaneously the observed properties of the present day galaxy population and the inter-galactic medium (e.g. EAGLE, Schaye et al. 2015, MNRAS, 446, 521; ILLUSTRIS, Vogelsberger et al., 2014, Nature, 509, 177). In particular, the luminosity and mass function of galaxies, the galaxy size- and metallicity-mass relations, and many other properties are now reproduced over a large range of galaxy stellar masses.

    The group of numerical astrophysics work on a variety of scientific topics related to the evolution of galaxies and the large-scale structure of the universe. The expertise ranges from the internal structure of dwarf and low surface brightness galaxies, the Milky Way and its satellite galaxies, the study of galaxies in groups and clusters, to large, cosmological simulations of the structure of the universe. The group collaborates with most of the IAC research groups working on extragalactic astrophysics and cosmology.

    Principal investigator
    Co Principal investigator
    Collaborators
    Prof.
    Sadegh Khochfar
    Prof.
    Joop Schaye
    Dr.
    Yannick Bahé
    Prof.
    Gustavo Yepes
    Prof.
    Daisuke Kawata
    Prof.
    Andrea Macciò
    Prof.
    Alexander Knebe
    Dr.
    Hidenobu Yashima

    EDGE/C-EAGLE With the completion of the main sample of simulations, the post-processing phase has been started. Dalla Vecchia developed an analysis program to compute luminosities of SSPs and magnitudes of galaxies of ~30 resimulated clusters. The code makes use of the stellar spectra library EMILES, developed at the IAC and recently extended to cover a larger wavelength range. EUCLID Within the EUCLID collaboration, a total of 300 cosmological, N-body simulations of a volume representative of the observed universe were performed. The same sample of initial conditions was evolved with different techniques by other members of the collaboration. The comparison of the different techniques will allow to assess their accuracy in the estimation of the covariance matrix, thus the errors in the measurements from large-scale structure surveys. GALAXY INTERACTIONS IN CLUSTERS For several decades, it has been known that stellar bars in disc galaxies can be triggered by interactions, or by internal processes such as dynamical instabilities. Martínez-Valpuesta et al. (2017) explore the differences between these two mechanisms using numerical simulations. They used two groups of simulations based on isolated galaxies, one group in which a bar develops naturally, and another group in which the bar could not develop in isolation. The rest of the simulations recreate 1:1 coplanar fly-by interactions computed with the impulse approximation. Compared with equivalent isolated galaxies, they find that bars affected or triggered by interactions: (i) remain in the slow regime for longer, (ii) are boxier in face-on views and (iii) they host kinematically hotter discs. Within this set of simulations, strong differences between retrograde or prograde fly-bys are not seen. They also show that slow interactions can trigger bar formation.

    Related publications

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      Numerical simulations within a cold dark matter (DM) cosmology form halos whose density profiles have a steep inner slope (‘cusp’), yet observations of galaxies often point towards a flat central ‘core’. We develop a convolutional mixture density neural network model to derive a probability density function (PDF) of the inner density slopes of DM

      Advertised on:

      12
      2022
    • The luminosity of cluster galaxies in the Cluster-EAGLE simulations

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      9
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    • NIHAO-LG: the uniqueness of Local Group dwarf galaxies

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      6
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    • Observed versus simulated halo c-M<SUB>vir</SUB> relations

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      Advertised on:

      2
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    • FOREVER22: galaxy formation in protocluster regions

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      1
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    • Formation of the first galaxies in the aftermath of the first supernovae

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      12
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    • A Shallow Dark Matter Halo in Ultra-diffuse Galaxy AGC 242019: Are UDGs Structurally Similar to Low-surface-brightness Galaxies?

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      Advertised on:

      9
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    • Pericentric passage-driven star formation in satellite galaxies and their hosts: CLUES from local group simulations

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      Advertised on:

      9
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    • Origin of stellar prolate rotation in a cosmologically simulated faint dwarf galaxy

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      Advertised on:

      7
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    • History of the gas fuelling star formation in EAGLE galaxies

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      8
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    • Higher order Hamiltonian Monte Carlo sampling for cosmological large-scale structure analysis

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      Hernández-Sánchez, Mónica et al.

      Advertised on:

      4
      2021
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    • Evaluating hydrodynamical simulations with green valley galaxies

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      Angthopo, J. et al.

      Advertised on:

      4
      2021
      Citations
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    • Self-interacting dark matter and the delay of supermassive black hole growth

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      Cruz, A. et al.

      Advertised on:

      1
      2021
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    • Stellar splashback: the edge of the intracluster light

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      Deason, Alis J. et al.

      Advertised on:

      1
      2021
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      22
    • The discovery of the most UV-Ly α luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosities

      We report the discovery of BOSS-EUVLG1 at z = 2.469, by far the most luminous, almost un-obscured star-forming galaxy known at any redshift. First classified as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up observations with the Gran Telescopio Canarias reveal that its large luminosity, MUV ≃ -24.40 and log(LLyα/erg s-1) ≃ 44

      Marques-Chaves, R. et al.

      Advertised on:

      9
      2020
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    • The First Billion Years project: Finding infant globular clusters at z = 6

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      Phipps, Frederika et al.

      Advertised on:

      9
      2020
      Citations
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    • NIHAO XXIV: rotation- or pressure-supported systems? Simulated Ultra Diffuse Galaxies show a broad distribution in their stellar kinematics

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      Advertised on:

      7
      2020
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    • Constraining the inner density slope of massive galaxy clusters

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      He, Qiuhan et al.

      Advertised on:

      6
      2020
      Citations
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    • Explaining the chemical trajectories of accreted and in-situ halo stars of the Milky Way

      The Milky Way underwent its last significant merger ten billion years ago, when the Gaia-Enceladus-Sausage (GES) was accreted. Accreted GES stars and progenitor stars born prior to the merger make up the bulk of the inner halo. Even though these two main populations of halo stars have similar durations of star formation prior to their merger, they

      Brook, Chris B. et al.

      Advertised on:

      4
      2020
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    • Kinematic analysis of eagle simulations: evolution of λ<SUB>Re</SUB> and its connection with mergers and gas accretion

      We have developed a new tool to analyse galaxies in the eagle simulations as close as possible to observations. We investigated the evolution of their kinematic properties by means of the angular momentum proxy parameter, λRe, for galaxies with M⋆ ≥ 5 × 109 M☉ in the RefL0100N1504 simulation up to redshift two (z = 2). Galaxies in the simulation

      Walo-Martín, D. et al.

      Advertised on:

      5
      2020
      Citations
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