The Low Redshift survey at Calar Alto (LoRCA)

TL;DR

The LoRCA project aims to measure the BAO standard ruler in the local universe with high precision to better understand dark energy, using a large spectroscopic galaxy survey and simulations to evaluate its effectiveness.

Contribution

This paper introduces the LoRCA survey, a new observational program targeting local galaxies to improve BAO measurements and dark energy constraints, supported by simulated light-cone analyses.

Findings

BAO can be measured with 4% precision using the survey data.

Reconstruction techniques improve BAO measurement accuracy to 1.2%.

The survey will significantly aid in understanding dark energy dynamics.

Abstract

The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of galaxies provides a standard ruler to measure the accelerated expansion of the Universe. To extract all available information about dark energy, it is necessary to measure a standard ruler in the local, z<0.2, universe where dark energy dominates most the energy density of the Universe. Though the volume available in the local universe is limited, it is just big enough to measure accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body simulations and approximate methods based on Lagrangian perturbation theory, we construct a suite of a thousand light-cones to evaluate the precision at which one can measure the BAO standard ruler in the local universe. We find that using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a precision of 4\% and 1.2\% using reconstruction). We also find that such a survey would help to detect the dynamics of dark energy.Therefore, we propose a 3-year long observational project, named the Low Redshift survey at Calar Alto (LoRCA), to observe spectroscopically about 200,000 galaxies in the northern sky to contribute to the construction of aforementioned galaxy sample. The suite of light-cones is made available to the public.