Cosmological Gas in RAMSES

The distribution of gas on cosmological scales is vital to our understanding of galaxy formation. Using the RAMSES cosmological hydrodynamical simulation code we have explored the evolution of the gas properties in a cosmological volume. We have identified the effect of the maximum simulation force resolution, and the resolution of the initial conditions, on the gas density power spectrum, as well as artefacts due to the RAMSES algorithm. The RAMSES methodology can add spurious power on small scales, particularly in low resolution simulations. This effect can be expected to have a strong impact on the results of RAMSES simulations, because this additional power appears at specific epochs, implying a sudden change to the system.