The cross-correlation between 21cm intensity mapping maps and the Lyman-alpha forest in the post-reionization era

Abstract

We investigate the cross-correlation signal between 21cm intensity mapping maps and the Lyman-alpha forest in the fully non-linear regime using state-of-the-art hydrodynamic simulations. The cross-correlation signal between these fields can provide a coherent and comprehensive picture of the neutral hydrogen (HI) content of our Universe in the post-reionization era, probing both its mass content and volume distribution. We compute the auto-power spectra of both fields together with their cross-power spectrum at z = 2.4 and find that on large scales the fields are completely anti-correlated. This anti-correlation arises because regions with high (low) 21cm emission, such as those with a large (low) concentration of damped Lyman-alpha systems, will show up as regions with low (high) transmitted flux. We find that on scales smaller than k = 0.2 h/Mpc the cross-correlation coefficient departs from -1, at a scale where non-linearities show up. We use the anisotropy of the power spectra in redshift-space to determine the values of the bias and of the redshift-space distortion parameters of both fields; we find that the errors on the value of these parameters could decrease by 30% when adding data from the cross-power spectrum in a conservative analysis. Our results point out that linear theory is capable of reproducing the shape and amplitude of the cross-power up to rather non-linear scales. Finally, we find that the 21cm-Lya cross-power spectrum can be detected by combining data from a BOSS-like survey together with 21cm intensity mapping observations by SKA1-MID with a S/N ratio higher than 3 in the range 0.06< k <1 h/Mpc. We emphasize that while the shape and amplitude of the 21cm auto-power spectrum can be severely affected by residual foreground contamination, cross-power spectra will be less sensitive to that and therefore can be used to identify systematics in the 21cm maps.

Accepted for publication in JCAP

References in corpus (13)

• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
• Late-time cosmology with 21cm intensity mapping experiments
• A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2
• Possibility of Precise Measurement of the Cosmological Power Spectrum With a Dedicated 21cm Survey After Reionization
• The Sherwood simulation suite: overview and data comparisons with the Lyman-alpha forest at redshifts 2 < z < 5
• Blind foreground subtraction for intensity mapping experiments
• An improved measurement of the flux distribution of the Ly-alpha forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties
• Voigt Profile Fitting to Quasar Absorption Lines: An Analytic Approximation to the Voigt-Hjerting Function
• Probing Reionization with the 21 cm-Galaxy Cross Power Spectrum
• Modeling the neutral hydrogen distribution in the post-reionization Universe: intensity mapping
• The Acoustic Peak in the Lyman Alpha Forest
• Cosmic Galaxy-IGM HI Relation at $z\sim 2-3$ Probed in the COSMOS/UltraVISTA $1.6$ deg${}^2$ Field

Cited by in corpus (24)

• Ingredients for 21cm intensity mapping
• 21cm foregrounds and polarization leakage: a user's guide on cleaning and mitigation strategies
• Singlet-Doublet Dark Matter Freeze-in: LHC displaced signatures versus cosmology
• Inflation and Early Dark Energy with a Stage II Hydrogen Intensity Mapping Experiment
• An Intensity Mapping Constraint on the CO-Galaxy Cross Power Spectrum at Redshift ~ 3
• Cross-correlating 21 cm and galaxy surveys: implications for cosmology and astrophysics
• Modelling the post-reionization neutral hydrogen ($\mathrm{HI}$) 21-cm bispectrum
• Redshift space distortions of the {\rm HI} 21-cm intensity mapping signal due to the internal motions within galaxies
• Cosmological Probes of Structure Growth and Tests of Gravity
• Imprints of non-standard Dark Energy and Dark Matter Models on the 21cm Intensity Map Power Spectrum
• Constraining dark energy using the cross correlations of weak lensing with post-reionization probes of neutral hydrogen
• Forecasts of cosmological constraints from HI intensity mapping with FAST, BINGO & SKA-I
• Extreme Spheres: Counts-in-cells for 21cm intensity mapping
• Post-reionization HI 21-cm signal: A probe of negative cosmological constant
• Predictions for measuring the cross power spectrum of the HI 21-cm signal and the Lyman-$\alpha$ forest using OWFA
• 21-cm foreground removal using AI and frequency-difference technique
• High-redshift test of gravity using enhanced growth of small structures probed by the neutral hydrogen distribution
• Unveiling the Universe with Emerging Cosmological Probes
• Constraining warm dark matter power spectrum using the cross-correlation of HI 21 cm signal and the Lyman-$\alpha$ forest
• Probing Quintessence using BAO imprint on the cross-correlation of weak lensing and post-reionization HI 21 cm signal
• Intensity mapping of post-reionization 21-cm signal and its cross-correlations as a probe of $f(R)$ gravity
• Reionization relics in the cross-correlation between the Ly$\alpha$ forest and 21 cm intensity mapping in the post-reionization era
• Combined lensed estimator to probe the post reionization H I power spectrum
• Probing dark energy using anisotropies in the clustering of post-EoR HI distribution