Gravitational Lensing of Cosmological 21cm Emission

Abstract

We investigate the feasibility of measuring weak gravitational lensing using 21cm intensity mapping with special emphasis on the performance of the planned Square Kilometre Array (SKA). We find that the current design for SKA-Mid should be able to measure the evolution of the lensing power spectrum at z~2-3 using this technique. This will be a probe of the expansion history of the universe and gravity at a unique range in redshift. The signal-to-noise is found to be highly dependent on evolution of the neutral hydrogen fraction in the universe with a higher HI density resulting in stronger signal. With realistic models for this, SKA Phase 1 should be capable of measuring the lensing power spectrum and its evolution. The signal-to-noise's dependence on the area and diameter of the telescope array is quantified. We further demonstrate the applications of this technique by applying it to two specific coupled dark energy models that would be difficult to observationally distinguish without information from this range of redshift. We also investigate measuring the lensing signal with 21cm emission from the Epoch of Reionization (EoR) using SKA-Low and find that it is unlikely to constrain cosmological parameters because of the small survey size, but could provide a map of the dark matter within a small region of the sky.

18 pages, 14 figures; version accepted for publication in MNRAS

References in corpus (8)

• Dynamics of dark energy
• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
• Future weak lensing constraints in a dark coupled universe
• Cosmological Information in the Gravitational Lensing of Pregalactic HI
• Weak Lensing Effects on the Galaxy Three-Point Correlation Function
• Galaxy-cluster masses via 21st-century measurements of lensing of 21-cm fluctuations

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• Simulations for 21 cm radiation lensing at EoR redshifts
• Full-Sky Lensing Reconstruction of 21 cm Intensity Maps
• Combined lensed estimator to probe the post reionization H I power spectrum
• Using strong gravitational lensing to probe the post reionization \HI power spectrum
• Probing dark energy using anisotropies in the clustering of post-EoR HI distribution
• Probing the Inflaton Potential with SKA