Constraints on ionising photon production from the large-scale Lyman-alpha forest

Abstract

Recent work has shown that the z~2.5 Lyman-alpha forest on large scales encodes information about the galaxy and quasar populations that keep the intergalactic medium photoionized. We present the first forecasts for constraining the populations with data from current and next-generation surveys. At a minimum the forest should tell us whether galaxies or, conversely, quasars dominate the photon production. The number density and clustering strength of the ionising sources might be estimated to sub-10% precision with a DESI-like survey if degeneracies (e.g., with the photon mean-free-path, small-scale clustering power normalization and potentially other astrophysical effects) can be broken by prior information. We demonstrate that, when inhomogeneous ionisation is correctly handled, constraints on dark energy do not degrade.

Matches version published in ApJL

References in corpus (3)

• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Minimally Parametric Power Spectrum Reconstruction from the Lyman-alpha Forest
• An unbiased measurement of the UV background and its evolution via the proximity effect in quasar spectra

Cited by in corpus (6)

• VoIgt profile Parameter Estimation Routine (VIPER): H I photoionization rate at z<0.5
• PRIYA: A New Suite of Lyman-alpha Forest Simulations for Cosmology
• Fresh Look at Neutrino Self-Interactions With the Lyman-$\alpha$ Forest: Constraints from EFT and PRIYA Simulations
• Forecasting constraints on the mean free path of ionizing photons at $z\ge 5.4$ from the Lyman-$\alpha$ forest flux auto-correlation function
• Boosting Line Intensity Map Signal-to-Noise with the Ly-$\alpha$ Forest Cross-Correlation
• Probing Large Scale Ionizing Background Fluctuation with Lyman $\alpha$ Forest and Galaxy Cross-correlation at z=2.4