SPH P3MG Simulations of the Lyman-alpha Forest
Wadsley, J. W. · Bond, J. Richard
Original · EN
Our understanding of the Lyman-α forest has received a great boost with the advent of the Keck Telescope and large 3D hydrodynamical simulations. We present new simulations using the SPH technique with a P³MG (Particle-Particle Particle-MultiGrid) non-periodic gravity solver. Our method employs a high resolution (1 kpc) inner volume, essential for capturing the complex gas physics, a larger low resolution volume, essential for correct larger scale tidal fields and a self-consistently applied, uniform tidal field to model the influence of ultra long waves. We include a photoionizing UV flux and relevant atomic cooling processes. We use constrained field realisations to probe a selection of environments and construct a statistical sample representative of the wider universe. We generate artificial Lyman-α spectra and fit Voigt profiles. We examine the importance of (1) the photoionizing flux level and history, (2) tidal environment and (3) differing cosmologies, including CDM and CDM+Λ. With an appropriate choice for the UV flux, we find that the data is fit quite well if the rms density contrast is 1 at z 3 on galaxy scales.
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