Quenched, bulge-dominated, but dynamically cold galaxies in IllustrisTNG and their real-world counterparts
Name
2107.07147.pdf
Description
Accepted version
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3.45 MB
Format
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Checksum (MD5)
9c49733867af20b9e3a0ac56357286ad
Author(s)
Lu, Shengdong
Xu, Dandan
Wang, Sen
Wang, Yunchong
Mao, Shude
Xia, Xiaoyang
Vogelsberger, Mark
Hernquist, Lars
Date Issued
2021
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Citation
Lu, Shengdong, Xu, Dandan, Wang, Sen, Wang, Yunchong, Mao, Shude et al. 2021. "Quenched, bulge-dominated, but dynamically cold galaxies in IllustrisTNG and their real-world counterparts." Monthly Notices of the Royal Astronomical Society, 509 (4).
Version
Author's final manuscript
Abstract
Galaxy morphologies, kinematics, and stellar populations are thought to be linked to each other. However, both simulations and observations have pointed out mismatches therein. In this work, we study the nature and origin of the present-day quenched, bulge-dominated, but dynamically cold galaxies within a stellar mass range of $10.3\, \leqslant \, \log \, M_{\ast }/\mathrm{M_{\odot }}\, \leqslant \, 11.2$ in the IllustrisTNG-100 Simulation. We compare these galaxies with a population of normal star-forming dynamically cold disc galaxies and a population of normal quenched dynamically hot elliptical galaxies within the same mass range. The populations of the present-day quenched and bulge-dominated galaxies (both being dynamically cold and hot) used to have significantly higher star formation rates and flatter morphologies at redshift of z ∼ 2. They have experienced more frequent larger mass-ratio mergers below z ∼ 0.7 in comparison to their star-forming disc counterparts, which is responsible for the formation of their bulge-dominated morphologies. The dynamically cold populations (both being star forming and quenched) have experienced more frequent prograde and tangential mergers especially below z ∼ 1, in contrast to the dynamically hot ellipticals, which have had more retrograde and radial mergers. Such different merging histories can well explain the differences on the cold and hot dynamical status among these galaxies. We point out that the real-world counterparts of these dynamically cold and hot bulge-dominated quenched populations are the fast- and slow-rotating early-type galaxies, respectively, as seen in observations and hence reveal the different evolution paths of these two distinct populations of early-type galaxies.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Attribution-NonCommercial-ShareAlike 4.0 International
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DOI of Published Version
https://doi.org/10.1093/MNRAS/STAB3228
