A study of stellar orbit fractions: simulated IllustrisTNG galaxies compared to CALIFA observations
Name
1905.11415.pdf
Description
Submitted version
Size
8.54 MB
Format
Unknown
Checksum (MD5)
a2710d494ebc71bfff644191380a5f02
Author(s)
Xu, Dandan
Zhu, Ling
Grand, Robert
Springel, Volker
Mao, Shude
van de Ven, Glenn
Lu, Shengdong
Wang, Yougang
Pillepich, Annalisa
Genel, Shy
Date Issued
2019
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Version
Original manuscript
Abstract
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society Motivated by the recently discovered kinematic 'Hubble sequence' shown by the stellar orbit-circularity distribution of 260 CALIFA galaxies, we make use of a comparable galaxy sample at z = 0 with a stellar mass range of M∗/M☉ ∈ [109.7, 1011.4] selected from the IllustrisTNG simulation and study their stellar orbit compositions in relation to a number of other fundamental galaxy properties. We find that the TNG100 simulation broadly reproduces the observed fractions of different orbital components and their stellar mass dependences. In particular, the mean mass dependences of the luminosity fractions for the kinematically warm and hot orbits are well reproduced within model uncertainties of the observed galaxies. The simulation also largely reproduces the observed peak and trough features at M∗ ≈ 1-2 × 1010 M☉ in the mean distributions of the cold- and hot-orbit fractions, respectively, indicating fewer cooler orbits and more hotter orbits in both more- and less-massive galaxies beyond such a mass range. Several marginal disagreements are seen between the simulation and observations: the average cold-orbit (counter-rotating) fractions of the simulated galaxies below (above) M∗ ≈ 6 × 1010 M☉ are systematically higher than the observational data by ≾ 10 per cent (absolute orbital fraction); the simulation also seems to produce more scatter for the cold-orbit fraction and less so for the non-cold orbits at any given galaxy mass. Possible causes that stem from the adopted heating mechanisms are discussed.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1093/MNRAS/STZ2164
