The edge of galaxy formation III: The effects of warm dark matter on Milky Way satellites and field dwarfs

Abstract

In this third paper of the series, we investigate the effects of warm dark matter with a particle mass of $m_{\mathrm{WDM}}=3\mathrm{keV}$ on the smallest galaxies in our Universe. We present a sample of 21 hydrodynamical cosmological simulations of dwarf galaxies and 20 simulations of satellite-host galaxy interaction that we performed both in a Cold Dark Matter (CDM) and Warm Dark Matter (WDM) scenario. In the WDM simulations, we observe a higher critical mass for the onset of star formation. Structure growth is delayed in WDM, as a result WDM haloes have a stellar population on average two Gyrs younger than their CDM counterparts. Nevertheless, despite this delayed star formation, CDM and WDM galaxies are both able to reproduce the observed scaling relations for velocity dispersion, stellar mass, size, and metallicity at $z=0$. WDM satellite haloes in a Milky Way mass host are more susceptible to tidal stripping due to their lower concentrations, but their galaxies can even survive longer than the CDM counterparts if they live in a dark matter halo with a steeper central slope. In agreement with our previous CDM satellite study we observe a steepening of the WDM satellites' central dark matter density slope due to stripping. The difference in the average stellar age for satellite galaxies, between CDM and WDM, could be used in the future for disentangling these two models.

10 pages, 11 figures, accepted for publication on MNRAS

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Cited by in corpus (8)

• WALLABY -- An SKA Pathfinder HI Survey
• Creating a galaxy lacking dark matter in a dark matter dominated universe
• Local Group star formation in warm and self-interacting dark matter cosmologies
• Matching the mass function of Milky Way satellites in competing dark matter models
• Clues to the nature of dark matter from first galaxies
• Warm dark matter model with a few keV mass is bad for the too-big-to-fail problem
• NIHAO-LG: The uniqueness of Local Group dwarf galaxies
• CASCO: Cosmological and AStrophysical parameters from Cosmological simulations and Observations IV. Testing warm dark matter cosmologies with galaxy scaling relations: A joint simulation-observation study using DREAMS simulations