Resolving the high redshift Lyman-alpha forest in smoothed particle hydrodynamics simulations

S. Bolton, James; D. Becker, George

Abstract

We use a large set of cosmological smoothed particle hydrodynamics (SPH) simulations to examine the effect of mass resolution and box size on synthetic Lya forest spectra at 2 \leq z \leq 5. The mass resolution requirements for the convergence of the mean Lya flux and flux power spectrum at z=5 are significantly stricter than at lower redshift. This is because transmission in the high redshift Lya forest is primarily due to underdense regions in the intergalactic medium (IGM), and these are less well resolved compared to the moderately overdense regions which dominate the Lya forest opacity at z~2-3. We further find that the gas density distribution in our simulations differs significantly from previous results in the literature at large overdensities (\Delta>10). We conclude that studies of the Lya forest at z=5 using SPH simulations require a gas particle mass of M_gas \leq 2x10^5 M_sol/h, which is >8 times the value required at z=2. A box size of at least 40 Mpc/h is preferable at all redshifts.

Citation

S. Bolton, J., & D. Becker, G. (2009). Resolving the high redshift Lyman-alpha forest in smoothed particle hydrodynamics simulations. Monthly Notices of the Royal Astronomical Society: Letters, 398(1), L26–L30. https://doi.org/10.1111/j.1745-3933.2009.00700.x

• Journal Article Type: Article
• Acceptance Date: Jun 12, 2009
• Online Publication Date: Sep 1, 2009
• Publication Date: 2009-09
• Deposit Date: Sep 16, 2019
• Publicly Available Date: Nov 3, 2019
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 398
• Issue: 1
• Pages: L26–L30
• DOI: https://doi.org/10.1111/j.1745-3933.2009.00700.x
• Keywords: Cosmology and Nongalactic Astrophysics
• Public URL: https://nottingham-repository.worktribe.com/output/2462296
• Publisher URL: https://academic.oup.com/mnrasl/article/398/1/L26/1039975
• Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters ©: 2009 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
• Contract Date: Nov 3, 2019