2016/10/28 by Connor Sheere, Alexander van Engelen, P. Daniel Meerburg +1
Physics and Astronomy · #Anisotropy #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Curl (programming language) #Galaxy #Gravitation #Gravitational lens #Gravitational wave #Optics #Photon #Physics #Polarization (electrochemistry) #Radio Astronomy Observations and Technology #Redshift #Reionization #Sky #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.96.063508
published as Phys. Rev. D 96, 063508 (2017) · 7 pages, 4 figures. Comments welcome
arxiv created 2016/10/28 · openalex created_date 2016/11/04 · openalex publication_date 2017/09/12 · arxiv updated 2017/09/20 · openalex updated_date 2026/08/05
Primordial gravitational waves leave a characteristic imprint on the cosmic microwave background (CMB) in the form of B-mode polarization. Photons are also deflected by large scale gravitational waves which intervene between the source screen and our telescopes, resulting in curl-type gravitational lensing. Gravitational waves present at the epoch of reionization contribute to both effects, thereby leading to a nonvanishing cross-correlation between B-mode polarization and curl lensing of the CMB. Observing such a cross-correlation would be very strong evidence that an observation of B-mode polarization was due to the presence of large scale gravitational waves, as opposed to astrophysical foregrounds or experimental systematic effects. We study the cross-correlation across a wide range of source redshifts and show that a post-SKA experiment aimed to map out the 21-cm sky between 15\ensuremath≤z\ensuremath≤30 could rule out non-zero cross-correlation at high significance for r\ensuremath≥0.01.