Hydrodynamical simulations of galaxy formation with non-Gaussian initial conditions

Clément Stahl, Yohan Dubois, Benoit Famaey, Oliver Hahn, Rodrigo Ibata, Katarina Kraljic, Thomas Montandon

Publications: Contribution to journalArticlePeer Reviewed

Abstract

Collisionless simulations of structure formation with significant local primordial non-Gaussianities at Mpc scales have shown that a non-Gaussian tail favouring underdensities, with a negative f NL parameter, can significantly change the merging history of galaxy-sized dark matter halos, which then typically assemble later than in vanilla ΛCDM. Moreover, such a small-scale negative f NL could have interesting consequences for the cosmological S 8 tension. Here, we complement our previous work on collisionless simulations with new hydrodynamical simulations of galaxy formation in boxes of 30 Mpc/h, using the RAMSES code. In particular, we show that all feedback prescriptions being otherwise identical, simulations with a negative f NL ∼ -1000 on small scales, hence forming galaxies a bit later than in vanilla ΛCDM, allow to form simulated galaxies with more disky kinematics than in the vanilla case. Therefore, such small-scale primordial non-Gaussianities could potentially help alleviate, simultaneously, tensions in cosmology and galaxy formation. These hydrodynamical simulations on small scales will need to be complemented with larger box simulations with scale-dependent non-Gaussianities, to statistically confirm these trends and explore their observational consequences in further detail.

Original languageEnglish
Article number036
Number of pages14
JournalJournal of Cosmology and Astroparticle Physics (JCAP)
Volume2023
Issue number9
DOIs
Publication statusPublished - 18 Sept 2023

Austrian Fields of Science 2012

  • 103004 Astrophysics
  • 103044 Cosmology
  • 103043 Computational physics

Keywords

  • Astrophysics - Cosmology and Nongalactic Astrophysics
  • Astrophysics - Astrophysics of Galaxies
  • cosmological simulations
  • galaxy formation
  • non-gaussianity
  • hydrodynamical simulations

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