Two shadows on two backlights: forecasting the Ly-$α$ forest $\times$ CMB Lensing bispectrum from ACT/SO/S4 & DESI

Fuente: arXiv
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Main Authors: La Posta, Adrien, Schaan, Emmanuel
Format: Preprint
Published: 2024
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author La Posta, Adrien
Schaan, Emmanuel
author_facet La Posta, Adrien
Schaan, Emmanuel
contents We forecast the sensitivity of future correlations between CMB lensing and the Lyman-$α$ forest power spectrum. This squeezed-limit bispectrum probes the connection between the Lyman-$α$ transmission and the underlying large-scale matter density field. We recover the measured signal-to-noise (SNR) ratio obtained with Planck$\times$BOSS, and forecast a SNR of $10.3, 14.8$ and $20.2$ for DESI combined with ACT, SO and CMB-S4 respectively. For DESI and SO/CMB-S4, the correlation should be detectable at SNR$\ge 5$ in 5 redshift bins, useful for distinguishing our signal from several contaminants.Indeed, our forecast is affected by large theoretical uncertainties in the current modeling of the signal and its contaminants, such as continuum misestimation bias or damped-Lyman-$α$ absorbers. Quantifying these more accurately will be crucial to enable a reliable cosmological interpretation of this observable in future measurements. We attempt to enumerate the features required in future Lyman-$α$ forest simulations required to do so.
format Preprint
id arxiv_https___arxiv_org_abs_2405_01628
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Two shadows on two backlights: forecasting the Ly-$α$ forest $\times$ CMB Lensing bispectrum from ACT/SO/S4 & DESI
La Posta, Adrien
Schaan, Emmanuel
Cosmology and Nongalactic Astrophysics
We forecast the sensitivity of future correlations between CMB lensing and the Lyman-$α$ forest power spectrum. This squeezed-limit bispectrum probes the connection between the Lyman-$α$ transmission and the underlying large-scale matter density field. We recover the measured signal-to-noise (SNR) ratio obtained with Planck$\times$BOSS, and forecast a SNR of $10.3, 14.8$ and $20.2$ for DESI combined with ACT, SO and CMB-S4 respectively. For DESI and SO/CMB-S4, the correlation should be detectable at SNR$\ge 5$ in 5 redshift bins, useful for distinguishing our signal from several contaminants.Indeed, our forecast is affected by large theoretical uncertainties in the current modeling of the signal and its contaminants, such as continuum misestimation bias or damped-Lyman-$α$ absorbers. Quantifying these more accurately will be crucial to enable a reliable cosmological interpretation of this observable in future measurements. We attempt to enumerate the features required in future Lyman-$α$ forest simulations required to do so.
title Two shadows on two backlights: forecasting the Ly-$α$ forest $\times$ CMB Lensing bispectrum from ACT/SO/S4 & DESI
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2405.01628