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Publication details for Dr Marius Constantin Cautun

Birkin, Jack, Li, Baojiu, Cautun, Marius & Shi, Yanlong (2019). Reconstructing the baryon acoustic oscillations using biased tracers. Monthly Notices of the Royal Astronomical Society 483(4): 5267-5280.

Author(s) from Durham


The reconstruction of the initial conditions of the Universe is an important topic in cosmology,
particularly in the context of sharpening the measurement of the baryon acoustic oscillation
(BAO) peak. Non-linear reconstruction algorithms developed in recent years, when applied
to late-time matter fields, can recover to a substantial degree the initial density distribution,
however, when applied to sparse tracers of the matter field, the performance is poorer. In
this paper, we apply the Shi et al. non-linear reconstruction method to biased tracers in order
to establish what factors affect the reconstruction performance. We find that grid resolution,
tracer number density, and mass assignment scheme all have a significant impact on the
performance of our reconstruction method, with triangular-shaped-cloud mass assignment
and a grid resolution of ∼1–2 h−1 Mpc being the optimal choice. We also show that our
method can be easily adapted to include generic tracer biases up to quadratic order in the
reconstruction formalism. Applying the reconstruction to halo and galaxy samples with a
range of tracer number densities, we find that the linear bias is by far the most important bias
term, while including non-local and non-linear biases only leads to marginal improvements
on the reconstruction performance. Overall, including bias in the reconstruction substantially
improves the recovery of BAO wiggles, down to k ∼ 0.25 h Mpc−1 for tracer number densities
between 2 × 10−4 and 2 × 10−3 ( h−1 Mpc)−3.