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

May 2, 2024
15 pages
e-Print:

Citations per year

0 Citations
Abstract: (arXiv)
We forecast the sensitivity of future correlations between CMB lensing and the Lyman-α\alpha forest power spectrum. This squeezed-limit bispectrum probes the connection between the Lyman-α\alpha transmission and the underlying large-scale matter density field. We recover the measured signal-to-noise (SNR) ratio obtained with Planck×\timesBOSS, and forecast a SNR of 10.3,14.810.3, 14.8 and 20.220.2 for DESI combined with ACT, SO and CMB-S4 respectively. For DESI and SO/CMB-S4, the correlation should be detectable at SNR5\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\alpha 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\alpha forest simulations required to do so.
Note:
  • 15 pages, 9 figures, Comments welcome