Laurin Söding

About me

Laurin Söding

3D Maps of the Interstellar Medium of the Milky Way

  • Atomic Hydrogen
    • Inferred from Galactic 21cm emission
  • Molecular Hydrogen
    • Inferred from \(J=1-0\) emission of CO
  • Joint inference of 3D gas densities, velocities, and line widths
  • Resolving the local bubble AND the Galactic large-scale structure
Top-down view of the total reconstructed Hydrogen density with a spiral model bei Reid et al. (2019) overlaid.
Top-down view of the total reconstructed Hydrogen density Σtot with the spiral model of Reid et al. (2019) overlaid. The position of the Sun is at (0,0). Positive x points towards the Galactic centre.
Samples from our estimation of the local dark matter density in comparison to other recent estimates using a vertical Jeans analysis

Dark matter in the Milky Way

  • Long-lived stellar populations are in (approximate) dynamical equilibrium with the Galactic disc
  • Data (number density and velocities) available via Gaia DR3, APOGEE, GALAH, GES, LAMOST, and RAVE
  • One part of the gravitational potential of the disc is sourced by dark matter
  • Component separation using Information Field Theory (IFT) gives dark matter density of \(\rho_\mathrm{dm} \approx 0.0117 \,\mathrm{M_\odot pc^{-3}}\)

Fuzzy dark matter structure formation in the early universe within kinetic field theory

  • Describing structure evolution using kinetic field theory, a statistical field theory for an ensemble of classical particles
  • The fuzzy dark matter power spectrum is suppressed initially and catches up to its cold dark matter counterpart at \(a \approx 0.15 \) for a particle mass of \(m_\mathrm{a}=10^{-22}\,\mathrm{eV}\)
4th order cumulants describing parts of the interactions beyond the Zel’dovich approximation in Kinetic Field Theory.
Bottom: Zoom-in view of a simulation showing a part of the cosmic web using a fuzzy dark matter model. Middle & Top: Cross-sections of my simulated filament showing interference effects

Simulating interference effects of axion dark matter

  • Modelling dark matter consisting of axions as a complex scalar field obeying the Schrödinger-Poisson system of equations
  • Studying the formation of interference fringes in simulations using a pseudo-spectral numerical solver
  • Results suggest a relationship between halo mass at time of first fringe formation and axion mass