Inflow velocities of cold flows streaming into massive galaxies at high redshifts
- Author(s)
- Tobias Goerdt, Daniel Ceverino
- Abstract
We study the velocities of the accretion along streams from the cosmic web into massive galaxies at high redshift with the help of three different suites of AMR hydrodynamical cosmological simulations. The results are compared to free-fall velocities and to the sound speeds of the hot ambient medium. The sound speed of the hot ambient medium is calculated using two different methods to determine the medium's temperature. We find that the simulated cold stream velocities are in violent disagreement with the corresponding free-fall profiles. The sound speed is a better albeit not always correct description of the cold flows' velocity. Using these calculations as a first order approximation for the gas inflow velocities v
inflow = 0.9 v
vir is given. We conclude from the hydrodynamical simulations as our main result that the velocity profiles for the cold streams are constant with radius. These constant inflow velocities seem to have a 'parabola-like' dependency on the host halo mass in units of the virial velocity that peaks at M
vir = 10
12 M⊙ and we also propose that the best-fitting functional form for the dependency of the inflow velocity on the redshift is a square root power-law relation: vinflow α √z + 1 v
vir.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Spanish National Research Council (CSIC)
- Journal
- Monthly Notices of the Royal Astronomical Society
- Volume
- 450
- Pages
- 3359 - 3370
- No. of pages
- 12
- ISSN
- 0035-8711
- DOI
- https://doi.org/10.1093/mnras/stv786
- Publication date
- 2015
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/f22802ed-a41a-479e-8791-3a445869807d