Morphological decomposition of TNG50 galaxies: methodology and catalogue
Abstract
We present MORDOR (MORphological DecOmposeR), a new algorithm for structural decomposition of simulated galaxies based on stellar kinematics. The code measures the properties of up to five structural components (a thin/cold and a thick/warm disc, a classical and a secular bulge, and a spherical stellar halo), and determines the properties of a stellar bar (if present). A comparison with other algorithms presented in the literature yields overall good agreement, with MORDOR displaying a higher flexibility in correctly decomposing systems and identifying bars in crowded environments (e.g. with ongoing fly-bys, often observable in cosmological simulations). We use MORDOR to analyse galaxies in the TNG50 simulation and find the following: (i) the thick disc component undergoes the strongest evolution in the binding energy-circularity plane, as expected when disc galaxies decrease their turbulent-rotational support with cosmic time; (ii) smaller galaxies (with stellar mass, $10^{9} \lesssim M_{*}/~\rm M_{\odot }\le 5 \times 10^{9}$) undergo a major growth in their disc components after z ~ 1, whereas (iii) the most massive galaxies ($5 \times 10^{10} \lt M_{*}/~\rm M_{\odot }\le 5\times 10^{11}$) evolve towards more spheroidal dominated objects down to z = 0 due to frequent gravitational interactions with satellites; (iv) the fraction of barred galaxies grows rapidly at high redshift and stabilizes below z ~ 2, except for the most massive galaxies that show a decrease in the bar occupation fraction at low redshift; (v) galaxies with $M_{*} \sim 10^{11}~~\rm M_{\odot }$ exhibit the highest relative occurrence of bars at z = 0, in agreement with observational studies. We publicly release MORDOR and the morphological catalogue of TNG50 galaxies.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2022
- DOI:
- 10.1093/mnras/stac1708
- arXiv:
- arXiv:2206.04693
- Bibcode:
- 2022MNRAS.515.1524Z
- Keywords:
-
- gravitation;
- methods: numerical;
- stars: kinematics and dynamics;
- galaxies: structure;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 20 pages, 20 figures. Submitted to MNRAS. MORDOR is available at https://github.com/thanatom/mordor. The catalogue is available at www.tng-project.org/zana22