High redshift measurements of the baryonic acoustic oscillation scale (BAO)
from large Ly-alpha forest surveys represent the next frontier of dark energy
studies. As part of this effort, efficient simulations of the BAO signature
from the Ly-alpha forest will be required. We construct a model for producing
fast, large volume simulations of the Ly-alpha forest for this purpose.
Utilising a calibrated semi-analytic approach, we are able to run very large
simulations in 1 Gpc^3 volumes which fully resolve the Jeans scale in less than
a day on a desktop PC using a GPU enabled version of our code. The Ly-alpha
forest spectra extracted from our semi-analytical simulations are in excellent
agreement with those obtained from a fully hydrodynamical reference simulation.
Furthermore, we find our simulated data are in broad agreement with
observational measurements of the flux probability distribution and 1D flux
power spectrum. We are able to correctly recover the input BAO scale from the
3D Ly-alpha flux power spectrum measured from our simulated data, and estimate
that a BOSS-like 10^4 deg^2 survey with ~15 background sources per square
degree and a signal-to-noise of ~5 per pixel should achieve a measurement of
the BAO scale to within ~1.4 per cent. We also use our simulations to provide
simple power-law expressions for estimating the fractional error on the BAO
scale on varying the signal-to-noise and the number density of background
sources. The speed and flexibility of our approach is well suited for exploring
parameter space and the impact of observational and astrophysical systematics
on the recovery of the BAO signature from forthcoming large scale spectroscopic
surveys.Comment: 16 pages, 11 figures, accepted to MNRA