6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
**Tours now open!** Registration is now closed - All registration payments are due before 23:39 SAST on 26 June.

The Stellar Mass–Spin Relation of Galaxies in Simba: The Role of Environment and Kinematic Morphology

7 Jul 2026, 12:20
20m
Lecture Hall C5 (University of the Western Cape)

Lecture Hall C5

University of the Western Cape

Oral Presentation Track D - Astrophysics & Space Science Astrophysics & Space Science

Speaker

Moorane Emily Makwela (student)

Description

We investigate whether the stellar mass–spin relation of galaxies depends on environment, and whether any such dependence is direct or mediated through galaxy morphology, using the Simba cosmological simulations . We construct a well-defined galaxy sample at redshift zero and measure the relation between stellar mass and specific angular momentum, quantifying its slope, normalisation, and intrinsic scatter. Residuals from this relation are analysed to identify secondary correlations with galaxy size and star-formation activity. Galaxies are classified into early- and late type systems using a kinematic morphology indicator based on rotational support. Environment is characterised through local density, host halo mass, central–satellite status, and intra-halo position. We first examine the dependence of spin on environment without controls, and then perform controlled tests at fixed stellar mass and morphology to isolate direct environmental effects. By explicitly disentangling morphology–environment coupling, we determine whether environmental trends arise primarily through changes in galaxy type or reflect an independent influence on angular momentum. Robustness tests ensure numerical stability. The results place quantitative constraints on the role of environment in shaping galaxy angular momentum and assess whether a null environmental dependence is consistent with the data.

Apply for student award at which level: MSc
Consent on use of personal information: Abstract Submission Yes, I ACCEPT

Author

Co-author

Presentation materials