WEAVE-QSO: A Massive Intergalactic Medium Survey for the William Herschel Telescope

TL;DR

The WEAVE-QSO survey aims to observe 400,000 high-redshift quasars to study the intergalactic medium, dark energy, and galaxy formation, utilizing the William Herschel Telescope starting in 2018.

Contribution

It introduces a large-scale quasar survey targeting the intergalactic medium to address key cosmological and galaxy formation questions with innovative target selection methods.

Findings

Will measure cosmic acceleration via Lyman-alpha forest analysis

Provides constraints on neutrino masses and dark matter properties

Studies gas properties across a wide range of densities and elements

Abstract

In these proceedings we describe the WEAVE-QSO survey, which will observe around 400,000 high redshift quasars starting in 2018. This survey is part of a broader WEAVE survey to be conducted at the 4.2m William Herschel Telescope. We will focus on chiefly on the science goals, but will also briefly summarise the target selection methods anticipated and the expected survey plan. Understanding the apparent acceleration in the expansion of the Universe is one of the key scientific challenges of our time. Many experiments have been proposed to study this expansion, using a variety of techniques. Here we describe a survey that can measure this acceleration and therefore help elucidate the nature of dark energy: a survey of the Lyman-alpha forest (and quasar absorption in general) in spectra towards z>2 quasars (QSOs). Further constraints on neutrino masses and warm dark matter are also anticipated. The same data will also shed light on galaxy formation via study of the properties of inflowing/outflowing gas associated with nearby galaxies and in a cosmic web context. Gas properties are sensitive to density, temperature, UV radiation, metallicity and abundance pattern, and so constraint galaxy formation in a variety of ways. WEAVE-QSO will study absorbers with a dynamic range spanning more than 8 orders of magnitude in column density, their thermal broadening, and a host of elements and ionization species. A core principal of the WEAVE-QSO survey is the targeting of QSOs with near 100% efficiency principally through use of the J-PAS (r < 23.2) and Gaia (r < 20) data.