Dark Matter Halo Spin of the Dwarf Galaxy UGC 5288: Insights from Observations, N-body and Cosmological Simulations

TL;DR

This paper introduces a hybrid observational and simulation-based method to estimate the dark matter halo spin of the dwarf galaxy UGC 5288, providing insights into its angular momentum profile.

Contribution

It develops a novel approach combining galaxy observations with N-body and cosmological simulations to estimate halo spin in gas-rich dwarf galaxies.

Findings

Simulated halo spin profiles match observed galaxy properties.

The estimated halo spin aligns with TNG50 simulation analogues.

Uncertainties arise from dark matter halo evolutionary history.

Abstract

Dark matter (DM) halo angular momentum is very challenging to determine from observations of galaxies. In this study, we present a new hybrid method of estimating the dimensionless halo angular momentum, halo spin of a gas-rich dwarf barred galaxy UGC5288 using N-Body/SPH simulations. We forward model the galaxy disk properties: stellar and gas mass, surface densities, disk scalelengths, bar length and bar ellipticity from observations. We use the HI rotation curve to constrain the DM halo density profile and further use the bar properties to determine the models that best represent the observed baryonic disk. We compare the halo spin profile from our models to the halo spin profiles of similar mass dwarf galaxy analogues of UGC5288 in the TNG50 simulations. The halo spin profile from our simulated models matches within ballpark values of the median spin profile of UGC5288 analogues in the TNG50 simulations, although there are some uncertainties due to the DM halo evolutionary history.