New method for initial density reconstruction

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. A theoretically interesting and practically important question in cosmology is the reconstruction of the initial density distribution provided a late-time density field. This is a long-standing question with a revived interest recently, especially in the context of optimally extracting the baryonic acoustic oscillation (BAO) signals from observed galaxy distributions. We present a new efficient method to carry out this reconstruction, which is based on numerical solutions to the nonlinear partial differential equation that governs the mapping between the initial Lagrangian and final Eulerian coordinates of particles in evolved density fields. This is motivated by numerical simulations of the quartic Galileon gravity model, which has similar equations that can be solved effectively by multigrid Gauss-Seidel relaxation. The method is based on mass conservation, and does not assume any specific cosmological model. Our test shows that it has a performance comparable to that of state-of-the-art algorithms that were very recently put forward in the literature, with the reconstructed density field over ∼80% (50%) correlated with the initial condition at k ≲ 0.6 h=Mpc (1.0 h=Mpc). With an example, we demonstrate that this method can significantly improve the accuracy of BAO reconstruction.

Measuring the baryon acoustic oscillation peak position with different galaxy selections

“…Eisenstein et al 2007b;Padmanabhan et al 2012) and the more recent non-linear reconstruction techniques (e.g. Ata et al 2015;Zhu et al 2017;Hada & Eisenstein 2018;Shi et al 2018;Birkin et al 2019;Jasche & Lavaux 2019). However, these methods are rather involved and it remains to be understood if they fully account for the BAO systematics present in different galaxy samples.…”

Tests of acoustic scale shifts in halo-based mock galaxy catalogues

“…The one-step version, known as standard reconstruction, has been field tested extensively with on-sky data (Padmanabhan et al 2012;Anderson et al 2012Anderson et al , 2014aKazin et al 2014;Ross et al 2017) and become part of the standard analysis procedure in modern galaxy redshift surveys. There has been much recent development in reconstruction (Seljak et al 2017;Schmittfull et al 2017;Shi et al 2018;Zhu et al 2018;Hada & Eisenstein 2018;Wang & Pen 2019). While standard reconstruction has worked well to restore and enhance the BAO signature, whether newer algorithms can perform better is a question.…”

Application of the iterative reconstruction to simulated galaxy fields

“…In addition, there are some different types of iterative reconstruction methods (e.g., Seo et al 2010;Tassev & Zaldarriaga 2012;Zhu et al 2017;Schmittfull et al 2017;Shi et al 2018). The main qualitative difference between our method and other iterative methods is that we take account of only the 1st order in LPT (simpler) while making the solution converge in the iteration process (more reliable).…”