%0 Generic %1 chen2021lyalpha %A Chen, Shi-Fan %A Vlah, Zvonimir %A White, Martin %D 2021 %K library %T The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective %U http://arxiv.org/abs/2103.13498 %X The Ly$\alpha$ forest provides one of the best means of mapping large-scale structure at high redshift, including our tightest constraint on the distance-redshift relation before cosmic noon. We describe how the large-scale correlations in the Ly$\alpha$ forest can be understood as an expansion in cumulants of the optical depth field, which itself can be related to the density field by a bias expansion. This provides a direct connection between the observable and the statistics of the matter fluctuations which can be computed in a systematic manner. We discuss the way in which complex, small-scale physics enters the predictions, the origin of the much-discussed velocity bias and the `renormalization' of the large-scale bias coefficients. Our calculations are within the context of perturbation theory, but we also make contact with earlier work using the peak-background split. Using the structure of the equations of motion we demonstrate, to all orders in perturbation theory, that the large-scale flux power spectrum becomes the linear spectrum times the square of a quadratic in the cosine of the angle to the line of sight. Unlike the case of galaxies, both the isotropic and anisotropic pieces receive contributions from small-scale physics.

@misc{chen2021lyalpha, abstract = {The Ly$\alpha$ forest provides one of the best means of mapping large-scale structure at high redshift, including our tightest constraint on the distance-redshift relation before cosmic noon. We describe how the large-scale correlations in the Ly$\alpha$ forest can be understood as an expansion in cumulants of the optical depth field, which itself can be related to the density field by a bias expansion. This provides a direct connection between the observable and the statistics of the matter fluctuations which can be computed in a systematic manner. We discuss the way in which complex, small-scale physics enters the predictions, the origin of the much-discussed velocity bias and the `renormalization' of the large-scale bias coefficients. Our calculations are within the context of perturbation theory, but we also make contact with earlier work using the peak-background split. Using the structure of the equations of motion we demonstrate, to all orders in perturbation theory, that the large-scale flux power spectrum becomes the linear spectrum times the square of a quadratic in the cosine of the angle to the line of sight. Unlike the case of galaxies, both the isotropic and anisotropic pieces receive contributions from small-scale physics.}, added-at = {2021-03-26T05:45:57.000+0100}, author = {Chen, Shi-Fan and Vlah, Zvonimir and White, Martin}, biburl = {https://www.bibsonomy.org/bibtex/25a2d4173a48522b951f90d6f1a4f0269/gpkulkarni}, description = {The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective}, interhash = {57f6207348508fd2ac6a34c611a77151}, intrahash = {5a2d4173a48522b951f90d6f1a4f0269}, keywords = {library}, note = {cite arxiv:2103.13498Comment: 26 pages, 4 figures, to be submitted to JCAP}, timestamp = {2021-03-26T05:45:57.000+0100}, title = {The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective}, url = {http://arxiv.org/abs/2103.13498}, year = 2021 }