Formation of massive disc galaxies in the IllustrisTNG simulation

Zeng, Guangquan; Wang, Lan; Gao, Liang

Abstract

We investigate the formation history of massive disc galaxies in hydrodynamical simulation – the IllustrisTNG, to study why massive disc galaxies survive through cosmic time. 83 galaxies in the simulation are selected with M*,z = 0 > 8 × 1010 M⊙ and kinematic bulge-to-total ratio less than 0.3. We find that 8.4 per cent of these massive disc galaxies have quiet merger histories and preserve disc morphology since formed. 54.2 per cent have a significant increase in bulge components in history, then become discs again till present time. The rest 37.3 per cent experience prominent mergers but survive to remain discy. While mergers and even major mergers do not always turn disc galaxies into ellipticals, we study the relations between various properties of mergers and the morphology of merger remnants. We find a strong dependence of remnant morphology on the orbit type of major mergers. Specifically, major mergers with a spiral-in falling orbit mostly lead to disc-dominant remnants, and major mergers of head-on galaxy–galaxy collision mostly form ellipticals. This dependence of remnant morphology on orbit type is much stronger than the dependence on cold gas fraction or orbital configuration of merger system as previously studied.

Citation

Zeng, G., Wang, L., & Gao, L. (2021). Formation of massive disc galaxies in the IllustrisTNG simulation. Monthly Notices of the Royal Astronomical Society, 507(3), 3301-3311. https://doi.org/10.1093/mnras/stab2294

• Journal Article Type: Article
• Acceptance Date: Aug 4, 2021
• Online Publication Date: Aug 10, 2021
• Publication Date: 2021-11
• Deposit Date: Nov 23, 2021
• Publicly Available Date: Nov 24, 2021
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 507
• Issue: 3
• Pages: 3301-3311
• DOI: https://doi.org/10.1093/mnras/stab2294
• Public URL: https://durham-repository.worktribe.com/output/1221076