The link between dwarf galaxy angular momentum and morphology

Leader: Sarah M. Sweet

Collaborators: Pratyush Das, Simon Deeley, others welcome

Topic: The unexpected dynamics of low-mass dwarf galaxies

Status: under review by Science Committee

Abstract: Dwarf galaxies are ideal tracers of angular momentum buildup, due to their susceptibility to environmental influences. In Deeley et al. in prep we use our bespoke method to measure angular momentum in a spatially resolved manner (without the underlying assumption of a settled disk) and find that the tight correlation between specific stellar angular momentum j* and stellar mass M* (the j*–M* relation) only holds down to masses larger than 10^8.5 Msol. Galaxies of lower masses have a wide range of angular momenta, appearing to correlate with dwarf morphology; disky dwarfs have j* consistent with the massive j*–M* relation, irregulars have low j* and dwarf spheroidals have a range of j*, including some above the j*–M* relation. In this paper we will investigate the connection between offset from the j*–M* relation and morphology using a larger sample of finely-resolved dwarfs. We will combine Spector maps with WALLABY 12″ maps where available to probe to higher radii and trace the bulk of the angular momentum, leading to a better characterisation of the kinematics. We will finally investigate the relative impact of the environment on the angular momentum and morphology of dwarf galaxies.

Needed data products: We need Spector stellar velocities and velocity dispersions, stellar mass maps, visual morphological classifications, WALLABY 12″ maps.

Publication Date: 07/02/2025