# Noise Estimates for Measurements of Weak Lensing from the Lyman-alpha Forest

## TL;DR

This paper estimates the noise in weak lensing measurements using the Lyman-alpha forest, demonstrating that current and future surveys can achieve high-precision cosmological insights at high redshift.

## Contribution

It introduces a method to estimate noise in Lyman-alpha forest lensing measurements and assesses the potential for high-precision cosmological mapping with existing and upcoming surveys.

## Key findings

- High-precision measurement of lensing power spectrum at z~2.5
- Potential for tomographic lensing analysis with multiple redshift bins
- Feasibility of mapping foreground matter distribution on degree scales

## Abstract

We have proposed a method for measuring weak lensing using the Lyman-alpha forest. Here we estimate the noise expected in weak lensing maps and power spectra for different sets of observational parameters. We find that surveys of the size and quality of the ones being done today and ones planned for the future will be able to measure the lensing power spectrum at a source redshift of z~2.5 with high precision and even be able to image the distribution of foreground matter with high fidelity on degree scales. For example, we predict that Lyman-alpha forest lensing measurement from the Dark Energy Spectroscopic Instrument survey should yield the mass fluctuation amplitude with statistical errors of 1.5%. By dividing the redshift range into multiple bins some tomographic lensing information should be accessible as well. This would allow for cosmological lensing measurements at higher redshift than are accessible with galaxy shear surveys and correspondingly better constraints on the evolution of dark energy at relatively early times.