Bibcode
Bryan, S. E.; Mao, S.; Kay, S. T.; Schaye, J.; Dalla Vecchia, C.; Booth, C. M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 422, Issue 3, pp. 1863-1879.
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5
2012
Citations
30
Refereed citations
29
Description
We explore the dynamical signatures imprinted by baryons on dark matter
haloes during the formation process using the OverWhelmingly Large
Simulations (OWLS), a set of state-of-the-art high-resolution
cosmological hydrodynamical simulations. We present a detailed study of
the effects of the implemented feedback prescriptions on the orbits of
dark matter particles, stellar particles and subhaloes, analysing runs
with no feedback, with stellar feedback and with feedback from
supermassive black holes. We focus on the central regions
(0.25r200) of haloes with virial masses ˜6 ×
1013 (˜7 × 1011) h-1
M⊙ at z= 0 (2). We also investigate how the orbital
content (relative fractions of the different orbital types) of these
haloes depends on several key parameters such as their mass, redshift
and dynamical state. The results of spectral analyses of the orbital
content of these simulations are compared, and the change in fraction of
box, tube and irregular orbits is quantified. Box orbits are found to
dominate the orbital structure of dark matter haloes in cosmological
simulations. There is a strong anticorrelation between the fraction of
box orbits and the central baryon fraction. While radiative cooling acts
to reduce the fraction of box orbits, strong feedback implementations
result in a similar orbital distribution to that of the dark matter only
case. The orbital content described by the stellar particles is found to
be remarkably similar to that drawn from the orbits of dark matter
particles, suggesting that either they have forgotten their dynamical
history, or subhaloes bringing in stars are not biased significantly
with respect to the main distribution. The orbital content of the
subhaloes is in broad agreement with that seen in the outer regions of
the particle distributions.