2014/11/30 by Toshiya Namikawa, Daisuke Yamauchi, Atsushi Taruya · 11 citations
Physics and Astronomy · #Astrophysics #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxy #Gravitational lens #Gravitational lensing formalism #Gravitational redshift #Gravitational wave #Optics #Physics #Polarization (electrochemistry) #Pulsars and Gravitational Waves Research #Radio Astronomy Observations and Technology #Redshift #Strong gravitational lensing #Weak gravitational lensing #astro-ph.CO #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.91.043531
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 91(4) (American Physical Society) · 9 pages, 4 figures, replaced to match the published version in PRD
openalex publication_date 2015/02/27 · arxiv created 2015/03/03 · arxiv updated 2015/03/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We discuss the future detectability of gravitational-wave induced lensing from high-sensitivity cosmic microwave background (CMB) experiments. Gravitational waves can induce a rotational component of the weak-lensing deflection angle, usually referred to as the curl mode, which would be imprinted on the CMB maps. Using the technique of reconstructing lensing signals involved in CMB maps, this curl mode can be measured in an unbiased manner, offering an independent confirmation of the gravitational waves complementary to B-mode polarization experiments. Based on the Fisher matrix analysis, we first show that with the noise levels necessary to confirm the consistency relation for the primordial gravitational waves, the future CMB experiments will be able to detect the gravitational-wave induced lensing signals. For a tensor-to-scalar ratio of r\ensuremath\lesssim0.1, even if the consistency relation is difficult to confirm with a high significance, the gravitational-wave induced lensing will be detected at more than 3\ensuremathσ significance level. Further, we point out that high-sensitivity experiments will be also powerful to constrain the gravitational waves generated after the recombination epoch. Compared to the B-mode polarization, the curl mode is particularly sensitive to gravitational waves generated at low redshifts (z\ensuremath\lesssim10) with a low frequency (k\ensuremath\lesssim10^\ensuremath-3 Mpc^\ensuremath-1), and it could give a much tighter constraint on their energy density \mathrm\ensuremathΩGW by more than 3 orders of magnitude.